diff --git a/homeassistant/components/synology_dsm/__init__.py b/homeassistant/components/synology_dsm/__init__.py
index ec93c92a698..ec13ec929a5 100644
--- a/homeassistant/components/synology_dsm/__init__.py
+++ b/homeassistant/components/synology_dsm/__init__.py
@@ -11,10 +11,10 @@ from synology_dsm.api.surveillance_station.camera import SynoCamera
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import CONF_MAC, CONF_VERIFY_SSL
 from homeassistant.core import HomeAssistant
-from homeassistant.exceptions import ConfigEntryAuthFailed, ConfigEntryNotReady
+from homeassistant.exceptions import ConfigEntryNotReady
 from homeassistant.helpers import config_validation as cv, device_registry as dr
 
-from .common import SynoApi
+from .common import SynoApi, raise_config_entry_auth_error
 from .const import (
     DEFAULT_VERIFY_SSL,
     DOMAIN,
@@ -68,11 +68,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     try:
         await api.async_setup()
     except SYNOLOGY_AUTH_FAILED_EXCEPTIONS as err:
-        if err.args[0] and isinstance(err.args[0], dict):
-            details = err.args[0].get(EXCEPTION_DETAILS, EXCEPTION_UNKNOWN)
-        else:
-            details = EXCEPTION_UNKNOWN
-        raise ConfigEntryAuthFailed(f"reason: {details}") from err
+        raise_config_entry_auth_error(err)
     except SYNOLOGY_CONNECTION_EXCEPTIONS as err:
         if err.args[0] and isinstance(err.args[0], dict):
             details = err.args[0].get(EXCEPTION_DETAILS, EXCEPTION_UNKNOWN)
@@ -147,8 +143,10 @@ async def async_remove_config_entry_device(
     """Remove synology_dsm config entry from a device."""
     data: SynologyDSMData = hass.data[DOMAIN][entry.unique_id]
     api = data.api
+    assert api.information is not None
     serial = api.information.serial
     storage = api.storage
+    assert storage is not None
     all_cameras: list[SynoCamera] = []
     if api.surveillance_station is not None:
         # get_all_cameras does not do I/O
diff --git a/homeassistant/components/synology_dsm/binary_sensor.py b/homeassistant/components/synology_dsm/binary_sensor.py
index 28dc750bc91..b9c7ff483ea 100644
--- a/homeassistant/components/synology_dsm/binary_sensor.py
+++ b/homeassistant/components/synology_dsm/binary_sensor.py
@@ -69,6 +69,7 @@ async def async_setup_entry(
     data: SynologyDSMData = hass.data[DOMAIN][entry.unique_id]
     api = data.api
     coordinator = data.coordinator_central
+    assert api.storage is not None
 
     entities: list[SynoDSMSecurityBinarySensor | SynoDSMStorageBinarySensor] = [
         SynoDSMSecurityBinarySensor(api, coordinator, description)
@@ -121,7 +122,8 @@ class SynoDSMSecurityBinarySensor(SynoDSMBinarySensor):
     @property
     def extra_state_attributes(self) -> dict[str, str]:
         """Return security checks details."""
-        return self._api.security.status_by_check  # type: ignore[no-any-return]
+        assert self._api.security is not None
+        return self._api.security.status_by_check
 
 
 class SynoDSMStorageBinarySensor(SynologyDSMDeviceEntity, SynoDSMBinarySensor):
diff --git a/homeassistant/components/synology_dsm/button.py b/homeassistant/components/synology_dsm/button.py
index 529682b4c6e..fccd0860036 100644
--- a/homeassistant/components/synology_dsm/button.py
+++ b/homeassistant/components/synology_dsm/button.py
@@ -73,7 +73,8 @@ class SynologyDSMButton(ButtonEntity):
         """Initialize the Synology DSM binary_sensor entity."""
         self.entity_description = description
         self.syno_api = api
-
+        assert api.network is not None
+        assert api.information is not None
         self._attr_name = f"{api.network.hostname} {description.name}"
         self._attr_unique_id = f"{api.information.serial}_{description.key}"
         self._attr_device_info = DeviceInfo(
@@ -82,6 +83,7 @@ class SynologyDSMButton(ButtonEntity):
 
     async def async_press(self) -> None:
         """Triggers the Synology DSM button press service."""
+        assert self.syno_api.network is not None
         LOGGER.debug(
             "Trigger %s for %s",
             self.entity_description.key,
diff --git a/homeassistant/components/synology_dsm/camera.py b/homeassistant/components/synology_dsm/camera.py
index 82d15138f05..901fcb1d565 100644
--- a/homeassistant/components/synology_dsm/camera.py
+++ b/homeassistant/components/synology_dsm/camera.py
@@ -42,6 +42,8 @@ class SynologyDSMCameraEntityDescription(
 ):
     """Describes Synology DSM camera entity."""
 
+    camera_id: int
+
 
 async def async_setup_entry(
     hass: HomeAssistant, entry: ConfigEntry, async_add_entities: AddEntitiesCallback
@@ -65,12 +67,13 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
         self,
         api: SynoApi,
         coordinator: SynologyDSMCameraUpdateCoordinator,
-        camera_id: str,
+        camera_id: int,
     ) -> None:
         """Initialize a Synology camera."""
         description = SynologyDSMCameraEntityDescription(
             api_key=SynoSurveillanceStation.CAMERA_API_KEY,
-            key=camera_id,
+            key=str(camera_id),
+            camera_id=camera_id,
             name=coordinator.data["cameras"][camera_id].name,
             entity_registry_enabled_default=coordinator.data["cameras"][
                 camera_id
@@ -85,23 +88,20 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
     @property
     def camera_data(self) -> SynoCamera:
         """Camera data."""
-        return self.coordinator.data["cameras"][self.entity_description.key]
+        return self.coordinator.data["cameras"][self.entity_description.camera_id]
 
     @property
     def device_info(self) -> DeviceInfo:
         """Return the device information."""
+        information = self._api.information
+        assert information is not None
         return DeviceInfo(
-            identifiers={
-                (
-                    DOMAIN,
-                    f"{self._api.information.serial}_{self.camera_data.id}",
-                )
-            },
+            identifiers={(DOMAIN, f"{information.serial}_{self.camera_data.id}")},
             name=self.camera_data.name,
             model=self.camera_data.model,
             via_device=(
                 DOMAIN,
-                f"{self._api.information.serial}_{SynoSurveillanceStation.INFO_API_KEY}",
+                f"{information.serial}_{SynoSurveillanceStation.INFO_API_KEY}",
             ),
         )
 
@@ -113,12 +113,12 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
     @property
     def is_recording(self) -> bool:
         """Return true if the device is recording."""
-        return self.camera_data.is_recording  # type: ignore[no-any-return]
+        return self.camera_data.is_recording
 
     @property
     def motion_detection_enabled(self) -> bool:
         """Return the camera motion detection status."""
-        return self.camera_data.is_motion_detection_enabled  # type: ignore[no-any-return]
+        return bool(self.camera_data.is_motion_detection_enabled)
 
     def _listen_source_updates(self) -> None:
         """Listen for camera source changed events."""
@@ -153,9 +153,10 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
         )
         if not self.available:
             return None
+        assert self._api.surveillance_station is not None
         try:
-            return await self._api.surveillance_station.get_camera_image(  # type: ignore[no-any-return]
-                self.entity_description.key, self.snapshot_quality
+            return await self._api.surveillance_station.get_camera_image(
+                self.entity_description.camera_id, self.snapshot_quality
             )
         except (
             SynologyDSMAPIErrorException,
@@ -178,7 +179,7 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
         if not self.available:
             return None
 
-        return self.camera_data.live_view.rtsp  # type: ignore[no-any-return]
+        return self.camera_data.live_view.rtsp
 
     async def async_enable_motion_detection(self) -> None:
         """Enable motion detection in the camera."""
@@ -186,8 +187,9 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
             "SynoDSMCamera.enable_motion_detection(%s)",
             self.camera_data.name,
         )
+        assert self._api.surveillance_station is not None
         await self._api.surveillance_station.enable_motion_detection(
-            self.entity_description.key
+            self.entity_description.camera_id
         )
 
     async def async_disable_motion_detection(self) -> None:
@@ -196,6 +198,7 @@ class SynoDSMCamera(SynologyDSMBaseEntity[SynologyDSMCameraUpdateCoordinator], C
             "SynoDSMCamera.disable_motion_detection(%s)",
             self.camera_data.name,
         )
+        assert self._api.surveillance_station is not None
         await self._api.surveillance_station.disable_motion_detection(
-            self.entity_description.key
+            self.entity_description.camera_id
         )
diff --git a/homeassistant/components/synology_dsm/common.py b/homeassistant/components/synology_dsm/common.py
index 42ec45e94a4..04e8ae29ceb 100644
--- a/homeassistant/components/synology_dsm/common.py
+++ b/homeassistant/components/synology_dsm/common.py
@@ -33,9 +33,15 @@ from homeassistant.const import (
     CONF_VERIFY_SSL,
 )
 from homeassistant.core import HomeAssistant, callback
+from homeassistant.exceptions import ConfigEntryAuthFailed
 from homeassistant.helpers.aiohttp_client import async_get_clientsession
 
-from .const import CONF_DEVICE_TOKEN, SYNOLOGY_CONNECTION_EXCEPTIONS
+from .const import (
+    CONF_DEVICE_TOKEN,
+    EXCEPTION_DETAILS,
+    EXCEPTION_UNKNOWN,
+    SYNOLOGY_CONNECTION_EXCEPTIONS,
+)
 
 LOGGER = logging.getLogger(__name__)
 
@@ -43,6 +49,8 @@ LOGGER = logging.getLogger(__name__)
 class SynoApi:
     """Class to interface with Synology DSM API."""
 
+    dsm: SynologyDSM
+
     def __init__(self, hass: HomeAssistant, entry: ConfigEntry) -> None:
         """Initialize the API wrapper class."""
         self._hass = hass
@@ -53,16 +61,15 @@ class SynoApi:
             self.config_url = f"http://{entry.data[CONF_HOST]}:{entry.data[CONF_PORT]}"
 
         # DSM APIs
-        self.dsm: SynologyDSM = None
-        self.information: SynoDSMInformation = None
-        self.network: SynoDSMNetwork = None
-        self.security: SynoCoreSecurity = None
-        self.storage: SynoStorage = None
-        self.photos: SynoPhotos = None
-        self.surveillance_station: SynoSurveillanceStation = None
-        self.system: SynoCoreSystem = None
-        self.upgrade: SynoCoreUpgrade = None
-        self.utilisation: SynoCoreUtilization = None
+        self.information: SynoDSMInformation | None = None
+        self.network: SynoDSMNetwork | None = None
+        self.security: SynoCoreSecurity | None = None
+        self.storage: SynoStorage | None = None
+        self.photos: SynoPhotos | None = None
+        self.surveillance_station: SynoSurveillanceStation | None = None
+        self.system: SynoCoreSystem | None = None
+        self.upgrade: SynoCoreUpgrade | None = None
+        self.utilisation: SynoCoreUtilization | None = None
 
         # Should we fetch them
         self._fetching_entities: dict[str, set[str]] = {}
@@ -85,7 +92,7 @@ class SynoApi:
             self._entry.data[CONF_USERNAME],
             self._entry.data[CONF_PASSWORD],
             self._entry.data[CONF_SSL],
-            timeout=self._entry.options.get(CONF_TIMEOUT),
+            timeout=self._entry.options.get(CONF_TIMEOUT) or 10,
             device_token=self._entry.data.get(CONF_DEVICE_TOKEN),
         )
         await self.dsm.login()
@@ -159,7 +166,8 @@ class SynoApi:
             return
 
         # surveillance_station is updated by own coordinator
-        self.dsm.reset(self.surveillance_station)
+        if self.surveillance_station:
+            self.dsm.reset(self.surveillance_station)
 
         # Determine if we should fetch an API
         self._with_system = bool(self.dsm.apis.get(SynoCoreSystem.API_KEY))
@@ -182,35 +190,40 @@ class SynoApi:
                 "Disable security api from being updated for '%s'",
                 self._entry.unique_id,
             )
-            self.dsm.reset(self.security)
+            if self.security:
+                self.dsm.reset(self.security)
             self.security = None
 
         if not self._with_photos:
             LOGGER.debug(
                 "Disable photos api from being updated or '%s'", self._entry.unique_id
             )
-            self.dsm.reset(self.photos)
+            if self.photos:
+                self.dsm.reset(self.photos)
             self.photos = None
 
         if not self._with_storage:
             LOGGER.debug(
                 "Disable storage api from being updatedf or '%s'", self._entry.unique_id
             )
-            self.dsm.reset(self.storage)
+            if self.storage:
+                self.dsm.reset(self.storage)
             self.storage = None
 
         if not self._with_system:
             LOGGER.debug(
                 "Disable system api from being updated for '%s'", self._entry.unique_id
             )
-            self.dsm.reset(self.system)
+            if self.system:
+                self.dsm.reset(self.system)
             self.system = None
 
         if not self._with_upgrade:
             LOGGER.debug(
                 "Disable upgrade api from being updated for '%s'", self._entry.unique_id
             )
-            self.dsm.reset(self.upgrade)
+            if self.upgrade:
+                self.dsm.reset(self.upgrade)
             self.upgrade = None
 
         if not self._with_utilisation:
@@ -218,7 +231,8 @@ class SynoApi:
                 "Disable utilisation api from being updated for '%s'",
                 self._entry.unique_id,
             )
-            self.dsm.reset(self.utilisation)
+            if self.utilisation:
+                self.dsm.reset(self.utilisation)
             self.utilisation = None
 
     async def _fetch_device_configuration(self) -> None:
@@ -272,11 +286,13 @@ class SynoApi:
 
     async def async_reboot(self) -> None:
         """Reboot NAS."""
-        await self._syno_api_executer(self.system.reboot)
+        if self.system:
+            await self._syno_api_executer(self.system.reboot)
 
     async def async_shutdown(self) -> None:
         """Shutdown NAS."""
-        await self._syno_api_executer(self.system.shutdown)
+        if self.system:
+            await self._syno_api_executer(self.system.shutdown)
 
     async def async_unload(self) -> None:
         """Stop interacting with the NAS and prepare for removal from hass."""
@@ -293,3 +309,12 @@ class SynoApi:
         LOGGER.debug("Start data update for '%s'", self._entry.unique_id)
         self._setup_api_requests()
         await self.dsm.update(self._with_information)
+
+
+def raise_config_entry_auth_error(err: Exception) -> None:
+    """Raise ConfigEntryAuthFailed if error is related to authentication."""
+    if err.args[0] and isinstance(err.args[0], dict):
+        details = err.args[0].get(EXCEPTION_DETAILS, EXCEPTION_UNKNOWN)
+    else:
+        details = EXCEPTION_UNKNOWN
+    raise ConfigEntryAuthFailed(f"reason: {details}") from err
diff --git a/homeassistant/components/synology_dsm/config_flow.py b/homeassistant/components/synology_dsm/config_flow.py
index c77b8196faf..785baa50b29 100644
--- a/homeassistant/components/synology_dsm/config_flow.py
+++ b/homeassistant/components/synology_dsm/config_flow.py
@@ -425,7 +425,7 @@ async def _login_and_fetch_syno_info(api: SynologyDSM, otp_code: str | None) ->
     ):
         raise InvalidData
 
-    return api.information.serial  # type: ignore[no-any-return]
+    return api.information.serial
 
 
 class InvalidData(HomeAssistantError):
diff --git a/homeassistant/components/synology_dsm/coordinator.py b/homeassistant/components/synology_dsm/coordinator.py
index bc896b1ad45..34886828a58 100644
--- a/homeassistant/components/synology_dsm/coordinator.py
+++ b/homeassistant/components/synology_dsm/coordinator.py
@@ -7,7 +7,10 @@ import logging
 from typing import Any, TypeVar
 
 from synology_dsm.api.surveillance_station.camera import SynoCamera
-from synology_dsm.exceptions import SynologyDSMAPIErrorException
+from synology_dsm.exceptions import (
+    SynologyDSMAPIErrorException,
+    SynologyDSMNotLoggedInException,
+)
 
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import CONF_SCAN_INTERVAL
@@ -15,10 +18,11 @@ from homeassistant.core import HomeAssistant
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 
-from .common import SynoApi
+from .common import SynoApi, raise_config_entry_auth_error
 from .const import (
     DEFAULT_SCAN_INTERVAL,
     SIGNAL_CAMERA_SOURCE_CHANGED,
+    SYNOLOGY_AUTH_FAILED_EXCEPTIONS,
     SYNOLOGY_CONNECTION_EXCEPTIONS,
 )
 
@@ -65,13 +69,17 @@ class SynologyDSMSwitchUpdateCoordinator(
     async def async_setup(self) -> None:
         """Set up the coordinator initial data."""
         info = await self.api.dsm.surveillance_station.get_info()
+        assert info is not None
         self.version = info["data"]["CMSMinVersion"]
 
     async def _async_update_data(self) -> dict[str, dict[str, Any]]:
         """Fetch all data from api."""
         surveillance_station = self.api.surveillance_station
+        assert surveillance_station is not None
         return {
-            "switches": {"home_mode": await surveillance_station.get_home_mode_status()}
+            "switches": {
+                "home_mode": bool(await surveillance_station.get_home_mode_status())
+            }
         }
 
 
@@ -96,14 +104,23 @@ class SynologyDSMCentralUpdateCoordinator(SynologyDSMUpdateCoordinator[None]):
 
     async def _async_update_data(self) -> None:
         """Fetch all data from api."""
-        try:
-            await self.api.async_update()
-        except SYNOLOGY_CONNECTION_EXCEPTIONS as err:
-            raise UpdateFailed(f"Error communicating with API: {err}") from err
+        for attempts in range(2):
+            try:
+                await self.api.async_update()
+            except SynologyDSMNotLoggedInException:
+                # If login is expired, try to login again
+                try:
+                    await self.api.dsm.login()
+                except SYNOLOGY_AUTH_FAILED_EXCEPTIONS as err:
+                    raise_config_entry_auth_error(err)
+                if attempts == 0:
+                    continue
+            except SYNOLOGY_CONNECTION_EXCEPTIONS as err:
+                raise UpdateFailed(f"Error communicating with API: {err}") from err
 
 
 class SynologyDSMCameraUpdateCoordinator(
-    SynologyDSMUpdateCoordinator[dict[str, dict[str, SynoCamera]]]
+    SynologyDSMUpdateCoordinator[dict[str, dict[int, SynoCamera]]]
 ):
     """DataUpdateCoordinator to gather data for a synology_dsm cameras."""
 
@@ -116,10 +133,11 @@ class SynologyDSMCameraUpdateCoordinator(
         """Initialize DataUpdateCoordinator for cameras."""
         super().__init__(hass, entry, api, timedelta(seconds=30))
 
-    async def _async_update_data(self) -> dict[str, dict[str, SynoCamera]]:
+    async def _async_update_data(self) -> dict[str, dict[int, SynoCamera]]:
         """Fetch all camera data from api."""
         surveillance_station = self.api.surveillance_station
-        current_data: dict[str, SynoCamera] = {
+        assert surveillance_station is not None
+        current_data: dict[int, SynoCamera] = {
             camera.id: camera for camera in surveillance_station.get_all_cameras()
         }
 
@@ -128,7 +146,7 @@ class SynologyDSMCameraUpdateCoordinator(
         except SynologyDSMAPIErrorException as err:
             raise UpdateFailed(f"Error communicating with API: {err}") from err
 
-        new_data: dict[str, SynoCamera] = {
+        new_data: dict[int, SynoCamera] = {
             camera.id: camera for camera in surveillance_station.get_all_cameras()
         }
 
diff --git a/homeassistant/components/synology_dsm/diagnostics.py b/homeassistant/components/synology_dsm/diagnostics.py
index d9b4131b078..42a8ab8d60f 100644
--- a/homeassistant/components/synology_dsm/diagnostics.py
+++ b/homeassistant/components/synology_dsm/diagnostics.py
@@ -4,8 +4,6 @@ from __future__ import annotations
 
 from typing import Any
 
-from synology_dsm.api.surveillance_station.camera import SynoCamera
-
 from homeassistant.components.camera import diagnostics as camera_diagnostics
 from homeassistant.components.diagnostics import async_redact_data
 from homeassistant.config_entries import ConfigEntry
@@ -47,7 +45,6 @@ async def async_get_config_entry_diagnostics(
     }
 
     if syno_api.network is not None:
-        intf: dict
         for intf in syno_api.network.interfaces:
             diag_data["network"]["interfaces"][intf["id"]] = {
                 "type": intf["type"],
@@ -55,7 +52,6 @@ async def async_get_config_entry_diagnostics(
             }
 
     if syno_api.storage is not None:
-        disk: dict
         for disk in syno_api.storage.disks:
             diag_data["storage"]["disks"][disk["id"]] = {
                 "name": disk["name"],
@@ -66,7 +62,6 @@ async def async_get_config_entry_diagnostics(
                 "size_total": disk["size_total"],
             }
 
-        volume: dict
         for volume in syno_api.storage.volumes:
             diag_data["storage"]["volumes"][volume["id"]] = {
                 "name": volume["fs_type"],
@@ -74,7 +69,6 @@ async def async_get_config_entry_diagnostics(
             }
 
     if syno_api.surveillance_station is not None:
-        camera: SynoCamera
         for camera in syno_api.surveillance_station.get_all_cameras():
             diag_data["surveillance_station"]["cameras"][camera.id] = {
                 "name": camera.name,
diff --git a/homeassistant/components/synology_dsm/entity.py b/homeassistant/components/synology_dsm/entity.py
index 4bd1e526194..1a2e07af9e1 100644
--- a/homeassistant/components/synology_dsm/entity.py
+++ b/homeassistant/components/synology_dsm/entity.py
@@ -45,16 +45,21 @@ class SynologyDSMBaseEntity(CoordinatorEntity[_CoordinatorT]):
         self.entity_description = description
 
         self._api = api
+        information = api.information
+        network = api.network
+        assert information is not None
+        assert network is not None
+
         self._attr_unique_id: str = (
-            f"{api.information.serial}_{description.api_key}:{description.key}"
+            f"{information.serial}_{description.api_key}:{description.key}"
         )
         self._attr_device_info = DeviceInfo(
-            identifiers={(DOMAIN, self._api.information.serial)},
-            name=self._api.network.hostname,
+            identifiers={(DOMAIN, information.serial)},
+            name=network.hostname,
             manufacturer="Synology",
-            model=self._api.information.model,
-            sw_version=self._api.information.version_string,
-            configuration_url=self._api.config_url,
+            model=information.model,
+            sw_version=information.version_string,
+            configuration_url=api.config_url,
         )
 
     async def async_added_to_hass(self) -> None:
@@ -85,14 +90,22 @@ class SynologyDSMDeviceEntity(
         self._device_model: str | None = None
         self._device_firmware: str | None = None
         self._device_type = None
+        storage = api.storage
+        information = api.information
+        network = api.network
+        assert information is not None
+        assert storage is not None
+        assert network is not None
 
         if "volume" in description.key:
-            volume = self._api.storage.get_volume(self._device_id)
+            assert self._device_id is not None
+            volume = storage.get_volume(self._device_id)
+            assert volume is not None
             # Volume does not have a name
             self._device_name = volume["id"].replace("_", " ").capitalize()
             self._device_manufacturer = "Synology"
-            self._device_model = self._api.information.model
-            self._device_firmware = self._api.information.version_string
+            self._device_model = information.model
+            self._device_firmware = information.version_string
             self._device_type = (
                 volume["device_type"]
                 .replace("_", " ")
@@ -100,7 +113,9 @@ class SynologyDSMDeviceEntity(
                 .replace("shr", "SHR")
             )
         elif "disk" in description.key:
-            disk = self._api.storage.get_disk(self._device_id)
+            assert self._device_id is not None
+            disk = storage.get_disk(self._device_id)
+            assert disk is not None
             self._device_name = disk["name"]
             self._device_manufacturer = disk["vendor"]
             self._device_model = disk["model"].strip()
@@ -109,11 +124,11 @@ class SynologyDSMDeviceEntity(
 
         self._attr_unique_id += f"_{self._device_id}"
         self._attr_device_info = DeviceInfo(
-            identifiers={(DOMAIN, f"{self._api.information.serial}_{self._device_id}")},
-            name=f"{self._api.network.hostname} ({self._device_name})",
+            identifiers={(DOMAIN, f"{information.serial}_{self._device_id}")},
+            name=f"{network.hostname} ({self._device_name})",
             manufacturer=self._device_manufacturer,
             model=self._device_model,
             sw_version=self._device_firmware,
-            via_device=(DOMAIN, self._api.information.serial),
+            via_device=(DOMAIN, information.serial),
             configuration_url=self._api.config_url,
         )
diff --git a/homeassistant/components/synology_dsm/manifest.json b/homeassistant/components/synology_dsm/manifest.json
index 8060bce5c9b..caecfcbd0c9 100644
--- a/homeassistant/components/synology_dsm/manifest.json
+++ b/homeassistant/components/synology_dsm/manifest.json
@@ -7,7 +7,7 @@
   "documentation": "https://www.home-assistant.io/integrations/synology_dsm",
   "iot_class": "local_polling",
   "loggers": ["synology_dsm"],
-  "requirements": ["py-synologydsm-api==2.1.4"],
+  "requirements": ["py-synologydsm-api==2.4.2"],
   "ssdp": [
     {
       "manufacturer": "Synology",
diff --git a/homeassistant/components/synology_dsm/media_source.py b/homeassistant/components/synology_dsm/media_source.py
index 9a393813c3e..4699a1a5c20 100644
--- a/homeassistant/components/synology_dsm/media_source.py
+++ b/homeassistant/components/synology_dsm/media_source.py
@@ -105,6 +105,7 @@ class SynologyPhotosMediaSource(MediaSource):
             ]
         identifier = SynologyPhotosMediaSourceIdentifier(item.identifier)
         diskstation: SynologyDSMData = self.hass.data[DOMAIN][identifier.unique_id]
+        assert diskstation.api.photos is not None
 
         if identifier.album_id is None:
             # Get Albums
@@ -112,6 +113,7 @@ class SynologyPhotosMediaSource(MediaSource):
                 albums = await diskstation.api.photos.get_albums()
             except SynologyDSMException:
                 return []
+            assert albums is not None
 
             ret = [
                 BrowseMediaSource(
@@ -148,6 +150,7 @@ class SynologyPhotosMediaSource(MediaSource):
             )
         except SynologyDSMException:
             return []
+        assert album_items is not None
 
         ret = []
         for album_item in album_items:
@@ -190,6 +193,8 @@ class SynologyPhotosMediaSource(MediaSource):
         self, item: SynoPhotosItem, diskstation: SynologyDSMData
     ) -> str | None:
         """Get thumbnail."""
+        assert diskstation.api.photos is not None
+
         try:
             thumbnail = await diskstation.api.photos.get_item_thumbnail_url(item)
         except SynologyDSMException:
@@ -215,13 +220,14 @@ class SynologyDsmMediaView(http.HomeAssistantView):
             raise web.HTTPNotFound
         # location: {cache_key}/{filename}
         cache_key, file_name = location.split("/")
-        image_id = cache_key.split("_")[0]
+        image_id = int(cache_key.split("_")[0])
         mime_type, _ = mimetypes.guess_type(file_name)
         if not isinstance(mime_type, str):
             raise web.HTTPNotFound
         diskstation: SynologyDSMData = self.hass.data[DOMAIN][source_dir_id]
 
-        item = SynoPhotosItem(image_id, "", "", "", cache_key, "")
+        assert diskstation.api.photos is not None
+        item = SynoPhotosItem(image_id, "", "", "", cache_key, "", False)
         try:
             image = await diskstation.api.photos.download_item(item)
         except SynologyDSMException as exc:
diff --git a/homeassistant/components/synology_dsm/sensor.py b/homeassistant/components/synology_dsm/sensor.py
index 6769c1e4901..b29a33f7253 100644
--- a/homeassistant/components/synology_dsm/sensor.py
+++ b/homeassistant/components/synology_dsm/sensor.py
@@ -292,6 +292,8 @@ async def async_setup_entry(
     data: SynologyDSMData = hass.data[DOMAIN][entry.unique_id]
     api = data.api
     coordinator = data.coordinator_central
+    storage = api.storage
+    assert storage is not None
 
     entities: list[SynoDSMUtilSensor | SynoDSMStorageSensor | SynoDSMInfoSensor] = [
         SynoDSMUtilSensor(api, coordinator, description)
@@ -299,21 +301,21 @@ async def async_setup_entry(
     ]
 
     # Handle all volumes
-    if api.storage.volumes_ids:
+    if storage.volumes_ids:
         entities.extend(
             [
                 SynoDSMStorageSensor(api, coordinator, description, volume)
-                for volume in entry.data.get(CONF_VOLUMES, api.storage.volumes_ids)
+                for volume in entry.data.get(CONF_VOLUMES, storage.volumes_ids)
                 for description in STORAGE_VOL_SENSORS
             ]
         )
 
     # Handle all disks
-    if api.storage.disks_ids:
+    if storage.disks_ids:
         entities.extend(
             [
                 SynoDSMStorageSensor(api, coordinator, description, disk)
-                for disk in entry.data.get(CONF_DISKS, api.storage.disks_ids)
+                for disk in entry.data.get(CONF_DISKS, storage.disks_ids)
                 for description in STORAGE_DISK_SENSORS
             ]
         )
diff --git a/homeassistant/components/synology_dsm/switch.py b/homeassistant/components/synology_dsm/switch.py
index c19cdb8c815..facce824bda 100644
--- a/homeassistant/components/synology_dsm/switch.py
+++ b/homeassistant/components/synology_dsm/switch.py
@@ -79,6 +79,8 @@ class SynoDSMSurveillanceHomeModeToggle(
 
     async def async_turn_on(self, **kwargs: Any) -> None:
         """Turn on Home mode."""
+        assert self._api.surveillance_station is not None
+        assert self._api.information
         _LOGGER.debug(
             "SynoDSMSurveillanceHomeModeToggle.turn_on(%s)",
             self._api.information.serial,
@@ -88,6 +90,8 @@ class SynoDSMSurveillanceHomeModeToggle(
 
     async def async_turn_off(self, **kwargs: Any) -> None:
         """Turn off Home mode."""
+        assert self._api.surveillance_station is not None
+        assert self._api.information
         _LOGGER.debug(
             "SynoDSMSurveillanceHomeModeToggle.turn_off(%s)",
             self._api.information.serial,
@@ -103,6 +107,9 @@ class SynoDSMSurveillanceHomeModeToggle(
     @property
     def device_info(self) -> DeviceInfo:
         """Return the device information."""
+        assert self._api.surveillance_station is not None
+        assert self._api.information is not None
+        assert self._api.network is not None
         return DeviceInfo(
             identifiers={
                 (
diff --git a/homeassistant/components/synology_dsm/update.py b/homeassistant/components/synology_dsm/update.py
index c7bcff48cea..ed60191f296 100644
--- a/homeassistant/components/synology_dsm/update.py
+++ b/homeassistant/components/synology_dsm/update.py
@@ -64,24 +64,29 @@ class SynoDSMUpdateEntity(
     @property
     def installed_version(self) -> str | None:
         """Version installed and in use."""
-        return self._api.information.version_string  # type: ignore[no-any-return]
+        assert self._api.information is not None
+        return self._api.information.version_string
 
     @property
     def latest_version(self) -> str | None:
         """Latest version available for install."""
+        assert self._api.upgrade is not None
         if not self._api.upgrade.update_available:
             return self.installed_version
-        return self._api.upgrade.available_version  # type: ignore[no-any-return]
+        return self._api.upgrade.available_version
 
     @property
     def release_url(self) -> str | None:
         """URL to the full release notes of the latest version available."""
+        assert self._api.information is not None
+        assert self._api.upgrade is not None
+
         if (details := self._api.upgrade.available_version_details) is None:
             return None
 
         url = URL("http://update.synology.com/autoupdate/whatsnew.php")
         query = {"model": self._api.information.model}
-        if details.get("nano") > 0:
+        if details["nano"] > 0:
             query["update_version"] = f"{details['buildnumber']}-{details['nano']}"
         else:
             query["update_version"] = details["buildnumber"]
diff --git a/requirements_all.txt b/requirements_all.txt
index 4d7edd2301e..54d136c0b83 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1634,7 +1634,7 @@ py-schluter==0.1.7
 py-sucks==0.9.9
 
 # homeassistant.components.synology_dsm
-py-synologydsm-api==2.1.4
+py-synologydsm-api==2.4.2
 
 # homeassistant.components.zabbix
 py-zabbix==1.1.7
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index ddb7061aee9..32bfdcd0968 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -1293,7 +1293,7 @@ py-nightscout==1.2.2
 py-sucks==0.9.9
 
 # homeassistant.components.synology_dsm
-py-synologydsm-api==2.1.4
+py-synologydsm-api==2.4.2
 
 # homeassistant.components.seventeentrack
 py17track==2021.12.2
diff --git a/tests/components/synology_dsm/test_media_source.py b/tests/components/synology_dsm/test_media_source.py
index 24e9a378c02..2a792d174f8 100644
--- a/tests/components/synology_dsm/test_media_source.py
+++ b/tests/components/synology_dsm/test_media_source.py
@@ -49,7 +49,9 @@ def dsm_with_photos() -> MagicMock:
 
     dsm.photos.get_albums = AsyncMock(return_value=[SynoPhotosAlbum(1, "Album 1", 10)])
     dsm.photos.get_items_from_album = AsyncMock(
-        return_value=[SynoPhotosItem(10, "", "filename.jpg", 12345, "10_1298753", "sm")]
+        return_value=[
+            SynoPhotosItem(10, "", "filename.jpg", 12345, "10_1298753", "sm", False)
+        ]
     )
     dsm.photos.get_item_thumbnail_url = AsyncMock(
         return_value="http://my.thumbnail.url"