Hi Stefano, I also have the same problem. I don't know how, but suddenly the camera and microphone are not working.
My laptop is HP x360 Convertible ab128tu. it has an integrated webcam which also includes microphone in it. around 2 weeks ago when I try to use it in zoom, it says there's no camera. and so is the microphone. i was kinda shocked.
After many attemps, I try your suggestion. It is indeed listed in the device manager as transparent after I click 'show hidden device'. I was glad that it worked.
I followed again your advice to 'uninstall device' so that it can get reinstalled after 'detect hardware change'.
but after I try to scan the change, it didn't do anything. the device is no longer listed and cannot get reinstalled automatically like you suggested somehow. Now I'm panicked.
What should I do in this situation?