diff --git a/build-scripts/bundle.cjs b/build-scripts/bundle.cjs
index df95d10d22..9c292c7921 100644
--- a/build-scripts/bundle.cjs
+++ b/build-scripts/bundle.cjs
@@ -92,8 +92,8 @@ module.exports.babelOptions = ({ latestBuild, isProdBuild, isTestBuild }) => ({
     [
       "@babel/preset-env",
       {
-        useBuiltIns: latestBuild ? false : "usage",
-        corejs: latestBuild ? false : dependencies["core-js"],
+        useBuiltIns: "usage",
+        corejs: dependencies["core-js"],
         bugfixes: true,
         shippedProposals: true,
       },
diff --git a/src/entrypoints/authorize.ts b/src/entrypoints/authorize.ts
index e26b398e7a..cc3e208d81 100644
--- a/src/entrypoints/authorize.ts
+++ b/src/entrypoints/authorize.ts
@@ -2,7 +2,6 @@
 import "../resources/compatibility";
 import "../auth/ha-authorize";
 import "../resources/safari-14-attachshadow-patch";
-import "../resources/array.flat.polyfill";
 
 import("../resources/ha-style");
 import("@polymer/polymer/lib/utils/settings").then(
diff --git a/src/entrypoints/core.ts b/src/entrypoints/core.ts
index e9bf6b4c00..bcd6138a0d 100644
--- a/src/entrypoints/core.ts
+++ b/src/entrypoints/core.ts
@@ -25,7 +25,6 @@ import { subscribePanels } from "../data/ws-panels";
 import { subscribeThemes } from "../data/ws-themes";
 import { subscribeUser } from "../data/ws-user";
 import type { ExternalAuth } from "../external_app/external_auth";
-import "../resources/array.flat.polyfill";
 import "../resources/safari-14-attachshadow-patch";
 
 window.name = MAIN_WINDOW_NAME;
diff --git a/src/entrypoints/onboarding.ts b/src/entrypoints/onboarding.ts
index 3d1ea41547..9deb735927 100644
--- a/src/entrypoints/onboarding.ts
+++ b/src/entrypoints/onboarding.ts
@@ -2,7 +2,6 @@
 import "../resources/compatibility";
 import "../onboarding/ha-onboarding";
 import "../resources/safari-14-attachshadow-patch";
-import "../resources/array.flat.polyfill";
 
 import("../resources/ha-style");
 import("@polymer/polymer/lib/utils/settings").then(
diff --git a/src/resources/array.flat.polyfill.ts b/src/resources/array.flat.polyfill.ts
deleted file mode 100644
index 61462cfb6d..0000000000
--- a/src/resources/array.flat.polyfill.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-/* eslint-disable no-extend-native */
-
-export {}; // for Babel to treat as a module
-
-if (!Array.prototype.flat) {
-  Object.defineProperty(Array.prototype, "flat", {
-    configurable: true,
-    writable: true,
-    value: function (...args) {
-      const depth = typeof args[0] === "undefined" ? 1 : Number(args[0]) || 0;
-      const result = [];
-      const forEach = result.forEach;
-
-      const flatDeep = (arr: Array<any>, dpth: number) => {
-        forEach.call(arr, (val) => {
-          if (dpth > 0 && Array.isArray(val)) {
-            flatDeep(val, dpth - 1);
-          } else {
-            result.push(val);
-          }
-        });
-      };
-
-      flatDeep(this, depth);
-      return result;
-    },
-  });
-}
diff --git a/src/resources/log-message.ts b/src/resources/log-message.ts
index 4372822c1f..28f810b897 100644
--- a/src/resources/log-message.ts
+++ b/src/resources/log-message.ts
@@ -1,4 +1,3 @@
-import "core-js/modules/web.url.can-parse";
 import { fromError } from "stacktrace-js";
 import { UAParser } from "ua-parser-js";