Understanding problem with project ID

Hello community,

I still have a problem understanding the project ID and therefore also the Firebase connection.
I created a project in Flutterflow "InventForMe24"
In addition, a Firebase database with the Firebase project ID "InventForMe24-a4xx2"
So far everything works.

If I now create a brunch, e.g. "main123456", and then use it, I have a new project ID in Flutter,
e.g. "InventForMe24-d-re34".

I can no longer access the database in Firebase.

Example:
Flutterflow project ID: InventForMe24-a4xx2
Firebase project ID: InventForMe24-a5cc3

I then duplicated a project in Futterflow.
I then entered the same Firebase settings in the duplicated project.
I can no longer access the database.

What am I doing wrong?

It is important to me that I can duplicate projects as a backup.
Now I help myself by creating snapshots.

Regards
Christian