Seems I have same issue as here: https://support.mozilla.org/en-US/questions/1328258 At some point (most of the time it seems after my laptop comes back from a sleep - like when moving back home from the office or when moving with the laptop from my desk into a meeting room), I try to get on a call on google meet and I get "no camera found". Fun stuff at the same time I can access the camera with Chrome with no issue. Seems a Firefox restart cleans up stuff and makes the camera accessible again, but I even believe I saw this working after I reconnected back from battery to ac.