Is it possible to use request.auth in firestore security rules when using a session cookie for authorization?

Consider the following Firestore Security rules

rules_version = '2';

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if request.auth != null;
    }
  }
}

This uses request.auth to check if the requesting user is authenticated. However, this rule fails when I use a sessionCookie for authorization, as described here.

Is it impossible to use request.auth when using a session cookie? Perhaps that's what's meant by

> For security reasons, Firebase session cookies cannot be used with other Firebase services due to their custom validity period, which can be set to the maximum duration of 2 weeks.

> Is it impossible to use request.auth when using a session cookie?

It is impossible. Session cookies are a way for passing data between your frontend and your backend, not between your frontend and Firebase backends. The Firebase SDKs handle the implementation of transfer of auth tokens to Firebase services.