You can simply use a non-Google email address to avoid Google avatar. However, connecting with Firebase’s customer support is better for a suitable answer. Similarly, this documentation page https://firebase.google.com/docs/genkit/plugins/firebase can also help you find more information about the auth plugin.
On the other hand, you can choose any cloud solution rather than Firebase. Indeed, Firebase has many alternatives like these, providing you with better user customization options. Likewise, you can select Amplify AWS or Back4app to manage users more appropriately.
Some more options could be:
- Backendless
- Kuzzle
- Supabase