Thanks. That's very helpful. You are welcome to try examining System Information > Hardware, but I am nearly certain it's going to indicate no FaceTime camera is installed.
There have been a number of substantially identical reports following the most recent macOS update, and an even greater number of alleged fixes. Most of them strike me as voodoo (such as the ones you tried) and none of them have resulted in a permanent fix.
Some Discussions posted just moments ago:
built in camera doesn't work
Camera is not working on my macbook pro
Rather than waste time chasing alleged fixes the only suggestion that makes any sense to me is to reinstall macOS from Recovery: Reinstall macOS - Apple Support. Unfortunately no one has yet followed up with a report of either success or failure. It's harmless enough to try though.
I have reason to believe it's a bug in that recent macOS update. If that's the case we will just have to wait for Apple to fix it.
Short of that you can restore a Time Machine backup of a system that predates that macOS update, but considering it was released over a week ago you may need to restore a lot of work created subsequent to that time.