You need to check the Firebase documentation for the upgrade to V9, and you need update your library react-firebase-hooks to 4.0.0 version (here documentation).

In your example, it would look like this:

import { useCollection } from 'react-firebase-hooks/firestore'
import { getFirestore, collection, query, where } from 'firebase/firestore'

const db = getFirestore(firebaseApp);

const q = query(collection(db, 'chats'), where('users', 'array-contains', user.email));
const [value, loading, error] = useCollection(
  q,
  { snapshotListenOptions: { includeMetadataChanges: true } }
)