The situation looks much better I could imagine.
First I tested the gcam good working with redmi 9.
Nikita GCam Port 7.4 from https://www.cyanogenmods.org/google-camera-redmi-9/
It works without problem , makes pictures and records movie.
Next I tested gcam 8.1 recomended for redmi 9 here :
forum.xda-developers.com
MGC_8.1.101_A9_PV0i_MGC.apk
This one the same good works.
Please test and write you opinion. Maybe create xml config file especial for m3 pro/note 10 5g ?
First I tested the gcam good working with redmi 9.
Nikita GCam Port 7.4 from https://www.cyanogenmods.org/google-camera-redmi-9/
It works without problem , makes pictures and records movie.
Next I tested gcam 8.1 recomended for redmi 9 here :

GCam with all 4 camera work
Download and install gcam from below link.. https://drive.google.com/file/d/1qQhQoMGMW2FX8a9gUxj2DYI4NeEx1l-K/view?usp=sharing Press on red circle button and observe if your camera change or not..if not then follow bellow instructions...

This one the same good works.
Please test and write you opinion. Maybe create xml config file especial for m3 pro/note 10 5g ?