For me using legacy Play Console Certificate key's SHA1 solved problem.

https://github.com/invertase/react-native-firebase/discussions/7293

• In local launch (emulator or connected devices), dubug key created in local needed. And we have to add Android Client in GCP OAuth 2.0 Client or Firebase Setting(Don't forget redownload google-services.json).
• In production (Play Console Internal Testing, Closed Testing, Open Testing, Production), normally we use Google Play signing, so Only Certificate key SHa1 needed. Upload key and SHA256 is not needed for me. Add Android Client with the SHA1 or add to Firebase Console.

If you are developing in one flavor (only production), you have to create Android Client or add SHA1 two in the GCP Projects.

Same package name must be set in Android app and GCP Android Client. And Don't use same package name in other project or even in other project's iOS Client.

This is my blog: https://qiita.com/maztak/items/3a57aff20a2cfe50adfc