diff --git a/packages/docusaurus-theme-classic/src/theme/hooks/useWindowSize.ts b/packages/docusaurus-theme-classic/src/theme/hooks/useWindowSize.ts
index 330869965fb4..84e60b168b58 100644
--- a/packages/docusaurus-theme-classic/src/theme/hooks/useWindowSize.ts
+++ b/packages/docusaurus-theme-classic/src/theme/hooks/useWindowSize.ts
@@ -51,9 +51,8 @@ function useWindowSize(): WindowSize {
       setWindowSize(getWindowSize());
     }
 
-    // @ts-expect-error: annoying TS setTimeout typing...
-    const timeout: number | undefined = DevSimulateSSR
-      ? setTimeout(updateWindowSize, 1000)
+    const timeout = DevSimulateSSR
+      ? window.setTimeout(updateWindowSize, 1000)
       : undefined;
 
     window.addEventListener('resize', updateWindowSize);
diff --git a/packages/docusaurus-theme-classic/src/types.d.ts b/packages/docusaurus-theme-classic/src/types.d.ts
index cabd03ed3e94..b1f9dba5d5f3 100644
--- a/packages/docusaurus-theme-classic/src/types.d.ts
+++ b/packages/docusaurus-theme-classic/src/types.d.ts
@@ -778,7 +778,7 @@ declare module '@theme/TagsListByLetter' {
 }
 
 declare module '@theme/TagsListInline' {
-  export type Tag = Readonly<{label: string; permalink}>;
+  export type Tag = Readonly<{label: string; permalink: string}>;
   export interface Props {
     readonly tags: readonly Tag[];
   }
diff --git a/packages/docusaurus-theme-common/src/components/Collapsible/index.tsx b/packages/docusaurus-theme-common/src/components/Collapsible/index.tsx
index 4be84b641d50..bcfd8e563ddb 100644
--- a/packages/docusaurus-theme-common/src/components/Collapsible/index.tsx
+++ b/packages/docusaurus-theme-common/src/components/Collapsible/index.tsx
@@ -189,7 +189,7 @@ function CollapsibleBase({
 
   return (
     <As
-      // @ts-expect-error: see https://twitter.com/sebastienlorber/status/1412784677795110914
+      // @ts-expect-error: the "too complicated type" is produced from "CollapsibleElementType" being a huge union
       ref={collapsibleRef}
       style={disableSSRStyle ? undefined : getSSRStyle(collapsed)}
       onTransitionEnd={(e: React.TransitionEvent) => {
diff --git a/packages/docusaurus-utils/src/index.ts b/packages/docusaurus-utils/src/index.ts
index cbba730789b1..e21f77c13123 100644
--- a/packages/docusaurus-utils/src/index.ts
+++ b/packages/docusaurus-utils/src/index.ts
@@ -18,7 +18,6 @@ import {
   TranslationFile,
 } from '@docusaurus/types';
 
-// @ts-expect-error: no typedefs :s
 import resolvePathnameUnsafe from 'resolve-pathname';
 
 import {posixPath as posixPathImport} from './posixPath';
diff --git a/packages/docusaurus-utils/src/types.d.ts b/packages/docusaurus-utils/src/types.d.ts
new file mode 100644
index 000000000000..79a7896f34cf
--- /dev/null
+++ b/packages/docusaurus-utils/src/types.d.ts
@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+declare module 'resolve-pathname' {
+  export default function resolvePathname(to: string, from?: string): string;
+}
diff --git a/packages/docusaurus/package.json b/packages/docusaurus/package.json
index 939c72d33ec2..2e681c6daf3c 100644
--- a/packages/docusaurus/package.json
+++ b/packages/docusaurus/package.json
@@ -35,7 +35,7 @@
     "@types/copy-webpack-plugin": "^8.0.1",
     "@types/css-minimizer-webpack-plugin": "^3.0.2",
     "@types/detect-port": "^1.3.0",
-    "@types/mini-css-extract-plugin": "^2.3.0",
+    "@types/mini-css-extract-plugin": "^1.4.3",
     "@types/module-alias": "^2.0.1",
     "@types/nprogress": "^0.2.0",
     "@types/react-dom": "^17.0.9",
diff --git a/packages/docusaurus/src/choosePort.ts b/packages/docusaurus/src/choosePort.ts
index 1a6583726836..0302b43acf94 100644
--- a/packages/docusaurus/src/choosePort.ts
+++ b/packages/docusaurus/src/choosePort.ts
@@ -87,8 +87,7 @@ export default async function choosePort(
   host: string,
   defaultPort: number,
 ): Promise<number | null> {
-  // @ts-expect-error: bad lib typedef?
-  return detect(defaultPort, host).then(
+  return detect({port: defaultPort, hostname: host}).then(
     (port) =>
       new Promise((resolve) => {
         if (port === defaultPort) {
diff --git a/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx b/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
index 98701a456cec..24e20d745440 100644
--- a/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
+++ b/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
@@ -23,6 +23,7 @@ describe('translate', () => {
   });
 
   test('reject when no id or message', () => {
+    // TODO tests are not resolving type defs correctly
     // @ts-expect-error: TS should protect when both id/message are missing
     expect(() => translate({})).toThrowErrorMatchingInlineSnapshot(
       `"Docusaurus translation declarations must have at least a translation id or a default translation message"`,
diff --git a/packages/docusaurus/src/types.d.ts b/packages/docusaurus/src/types.d.ts
index 57e8b4c0a8a4..d543d4c85218 100644
--- a/packages/docusaurus/src/types.d.ts
+++ b/packages/docusaurus/src/types.d.ts
@@ -9,7 +9,9 @@ declare module 'remark-admonitions';
 
 declare module 'react-loadable-ssr-addon-v5-slorber';
 
-declare module 'resolve-pathname';
+declare module 'resolve-pathname' {
+  export default function resolvePathname(to: string, from?: string): string;
+}
 
 declare module '@slorber/static-site-generator-webpack-plugin';
 
diff --git a/packages/docusaurus/src/webpack/utils.ts b/packages/docusaurus/src/webpack/utils.ts
index f6e02283d996..4d75cb0d40c0 100644
--- a/packages/docusaurus/src/webpack/utils.ts
+++ b/packages/docusaurus/src/webpack/utils.ts
@@ -10,7 +10,6 @@ import {
   mergeWithCustomize,
   customizeArray,
   customizeObject,
-  CustomizeRule,
 } from 'webpack-merge';
 import webpack, {
   Configuration,
@@ -224,8 +223,7 @@ export function applyConfigureWebpack(
       content,
     );
     if (res && typeof res === 'object') {
-      // @ts-expect-error: annoying error due to enums: https://github.com/survivejs/webpack-merge/issues/179
-      const customizeRules: Record<string, CustomizeRule> = mergeStrategy ?? {};
+      const customizeRules = mergeStrategy ?? {};
       return mergeWithCustomize({
         customizeArray: customizeArray(customizeRules),
         customizeObject: customizeObject(customizeRules),
diff --git a/yarn.lock b/yarn.lock
index 3ceb217f44c9..bfceb86164c1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4280,10 +4280,10 @@
   resolved "https://registry.yarnpkg.com/@types/mime/-/mime-1.3.2.tgz#93e25bf9ee75fe0fd80b594bc4feb0e862111b5a"
   integrity sha512-YATxVxgRqNH6nHEIsvg6k2Boc1JHI9ZbH5iWFFv/MTkchz3b1ieGDa5T0a9RznNdI0KhVbdbWSN+KWWrQZRxTw==
 
-"@types/mini-css-extract-plugin@^2.3.0":
-  version "2.3.0"
-  resolved "https://registry.yarnpkg.com/@types/mini-css-extract-plugin/-/mini-css-extract-plugin-2.3.0.tgz#2637bc09347ffa21b75f91b93dd00ce3d3971872"
-  integrity sha512-DeEkl1HsCDij3P7tfIWhQENVXz4wE17Ew0+5+KRh5HAcFcIZMfQg4HxKwEIqulVALYyv7JKisn4BPu3f7OHPVQ==
+"@types/mini-css-extract-plugin@^1.4.3":
+  version "1.4.3"
+  resolved "https://registry.yarnpkg.com/@types/mini-css-extract-plugin/-/mini-css-extract-plugin-1.4.3.tgz#4907ee3953fecd199fab24ef056dabef51ff19a2"
+  integrity sha512-jyOSVaF4ie2jUGr1uohqeyDrp7ktRthdFxDKzTgbPZtl0QI5geEopW7UKD/DEfn0XgV1KEq/RnZlUmnrEAWbmg==
   dependencies:
     "@types/node" "*"
     tapable "^2.2.0"
@@ -20371,9 +20371,9 @@ webpack-sources@^3.2.0:
   integrity sha512-t6BMVLQ0AkjBOoRTZgqrWm7xbXMBzD+XDq2EZ96+vMfn3qKgsvdXZhbPZ4ElUOpdv4u+iiGe+w3+J75iy/bYGA==
 
 webpack@^5, webpack@^5.1.0, webpack@^5.37.0, webpack@^5.40.0:
-  version "5.54.0"
-  resolved "https://registry.yarnpkg.com/webpack/-/webpack-5.54.0.tgz#629f0cd14c7a4340af758a3c7cef25c50670ae4d"
-  integrity sha512-MAVKJMsIUotOQKzFOmN8ZkmMlj7BOyjDU6t1lomW9dWOme5WTStzGa3HMLdV1KYD1AiFETGsznL4LMSvj4tukw==
+  version "5.59.1"
+  resolved "https://registry.yarnpkg.com/webpack/-/webpack-5.59.1.tgz#60c77e9aad796252153d4d7ab6b2d4c11f0e548c"
+  integrity sha512-I01IQV9K96FlpXX3V0L4nvd7gb0r7thfuu1IfT2P4uOHOA77nKARAKDYGe/tScSHKnffNIyQhLC8kRXzY4KEHQ==
   dependencies:
     "@types/eslint-scope" "^3.7.0"
     "@types/estree" "^0.0.50"