How to fix Firebase admin verifyIdToken is not a function

I'm working through Lee Robinson's React 2025 course and I'm experiencing an issue while trying to verify an ID token through Firebase admin. The closest issue I can find is this but the solutions didn't work for me.

The error I got is:

TypeError: firebase_admin__WEBPACK_IMPORTED_MODULE_1__.auth.verifyIdToken is not a function
at __webpack_exports__.default (webpack-internal:///./pages/api/notes.js:10:65)
at apiResolver (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/api-utils.js:8:7)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:93:5)
at async DevServer.handleApiRequest (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/next-server.js:63:403)
at async Object.fn (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/next-server.js:55:530)
at async Router.execute (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/router.js:24:67)
at async DevServer.run (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/next-server.js:65:1023)
at async DevServer.handleRequest (/Users/Alfred/Documents/Alfred/Coding/augment-notes/augment-notes/node_modules/next/dist/next-server/server/next-server.js:33:450)

Here are the relevant files:

firebase-admin.js

import admin from 'firebase-admin';

if (!admin.apps.length) {
  admin.initializeApp({
    credential: admin.credential.cert({
      project_id: process.env.NEXT_PUBLIC_FIREBASE_PROJECT_ID,
      private_key: process.env.FIREBASE_PRIVATE_KEY,
      client_email: process.env.FIREBASE_CLIENT_EMAIL,
    }),
    databaseURL: '<my database url, removed for this post>',
  });
}

const db = admin.firestore();
const auth = admin.auth();

export { db, auth };

notes.js

import { getUserNotes } from '@/lib/db-admin';
import { auth } from 'firebase-admin';

export default async (req, res) => {
  const { uid } = await auth.verifyIdToken(req.headers.token);
  const { notes } = await getUserNotes(uid);

  res.status(200).json({ notes });
};

I don't think it's an issue with my Firebase admin SDK setup because I can fetch data from the database if I remove the verifyIdToken method and insert a uid directly.

If I should provide more information, please let me know. Thank you!