diff --git a/homeassistant/components/mqtt/client.py b/homeassistant/components/mqtt/client.py
index 2fca77ba25f..3fbd26e2e7f 100644
--- a/homeassistant/components/mqtt/client.py
+++ b/homeassistant/components/mqtt/client.py
@@ -317,8 +317,8 @@ class MqttClientSetup:
         client_cert = get_file_path(CONF_CLIENT_CERT, config.get(CONF_CLIENT_CERT))
         tls_insecure = config.get(CONF_TLS_INSECURE)
         if transport == TRANSPORT_WEBSOCKETS:
-            ws_path = config.get(CONF_WS_PATH)
-            ws_headers = config.get(CONF_WS_HEADERS)
+            ws_path: str = config[CONF_WS_PATH]
+            ws_headers: dict[str, str] = config[CONF_WS_HEADERS]
             self._client.ws_set_options(ws_path, ws_headers)
         if certificate is not None:
             self._client.tls_set(
@@ -340,6 +340,8 @@ class MqttClientSetup:
 class MQTT:
     """Home Assistant MQTT client."""
 
+    _mqttc: mqtt.Client
+
     def __init__(
         self,
         hass: HomeAssistant,
@@ -347,10 +349,6 @@ class MQTT:
         conf: ConfigType,
     ) -> None:
         """Initialize Home Assistant MQTT client."""
-        # We don't import on the top because some integrations
-        # should be able to optionally rely on MQTT.
-        import paho.mqtt.client as mqtt  # pylint: disable=import-outside-toplevel
-
         self._mqtt_data = get_mqtt_data(hass)
 
         self.hass = hass
@@ -360,7 +358,6 @@ class MQTT:
         self.connected = False
         self._ha_started = asyncio.Event()
         self._last_subscribe = time.time()
-        self._mqttc: mqtt.Client = None
         self._cleanup_on_unload: list[Callable[[], None]] = []
 
         self._paho_lock = asyncio.Lock()  # Prevents parallel calls to the MQTT client
@@ -526,12 +523,9 @@ class MQTT:
         """
 
         def _client_unsubscribe(topic: str) -> int:
-            result: int | None = None
-            mid: int | None = None
             result, mid = self._mqttc.unsubscribe(topic)
             _LOGGER.debug("Unsubscribing from %s, mid: %s", topic, mid)
             _raise_on_error(result)
-            assert mid
             return mid
 
         if any(other.topic == topic for other in self.subscriptions):
@@ -563,8 +557,8 @@ class MQTT:
                 _process_client_subscriptions
             )
 
-        tasks = []
-        errors = []
+        tasks: list[Coroutine[Any, Any, None]] = []
+        errors: list[int] = []
         for result, mid in results:
             if result == 0:
                 tasks.append(self._wait_for_mid(mid))
@@ -777,7 +771,7 @@ class MQTT:
             )
 
 
-def _raise_on_errors(result_codes: Iterable[int | None]) -> None:
+def _raise_on_errors(result_codes: Iterable[int]) -> None:
     """Raise error if error result."""
     # pylint: disable-next=import-outside-toplevel
     import paho.mqtt.client as mqtt
@@ -790,7 +784,7 @@ def _raise_on_errors(result_codes: Iterable[int | None]) -> None:
         raise HomeAssistantError(f"Error talking to MQTT: {', '.join(messages)}")
 
 
-def _raise_on_error(result_code: int | None) -> None:
+def _raise_on_error(result_code: int) -> None:
     """Raise error if error result."""
     _raise_on_errors((result_code,))
 
diff --git a/homeassistant/components/mqtt/util.py b/homeassistant/components/mqtt/util.py
index 97bb120f842..25fb71831bc 100644
--- a/homeassistant/components/mqtt/util.py
+++ b/homeassistant/components/mqtt/util.py
@@ -177,7 +177,7 @@ async def async_create_certificate_temp_files(
     await hass.async_add_executor_job(_create_temp_dir_and_files)
 
 
-def get_file_path(option: str, default: str | None = None) -> Path | str | None:
+def get_file_path(option: str, default: str | None = None) -> str | None:
     """Get file path of a certificate file."""
     temp_dir = Path(tempfile.gettempdir()) / TEMP_DIR_NAME
     if not temp_dir.exists():
@@ -187,7 +187,7 @@ def get_file_path(option: str, default: str | None = None) -> Path | str | None:
     if not file_path.exists():
         return default
 
-    return temp_dir / option
+    return str(temp_dir / option)
 
 
 def migrate_certificate_file_to_content(file_name_or_auto: str) -> str | None:
diff --git a/requirements_test.txt b/requirements_test.txt
index 9590cc0b95c..b6d48698690 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -39,6 +39,7 @@ types-chardet==0.1.5
 types-decorator==0.1.7
 types-enum34==0.1.8
 types-ipaddress==0.1.5
+types-paho-mqtt==1.6.0.1
 types-pkg-resources==0.1.3
 types-python-dateutil==2.8.19.2
 types-python-slugify==0.1.2