I can't use the keyboard

Android Tablets HiPad Plus
1

I can’t use the keyboard

I could use a Bluetooth keyboard on Android 10, but not on Android 11.
The mouse recognizes it as a keyboard. The keyboard is not recognized even if the mouse is disconnected.

Can be connected to a keyboard
No key entered

2

I have a Bluetooth connection, but I can’t use it
Not even displayed as a hardware keyboard

I use 80% with a physical keyboard, so please tell me how to use it

3

I tried to use keyboards on other tablets - they work disgustingly, godlessly buggy. Better use the onscreen keyboard.