Q1 : Microphone, Webcam, Screen sharing do not work on macOS due to permission
Example errors
There was an issue with your media devices
Webcam settings : NotAllowedError: Permission denied by system
Error: Permission to access screen wasn't granted.
Since macOS only grants an access to Microphone, Camera, Screen Recording per Application.
It is required to give those permission to your browser to use full functionality of this system.
Choose System Preferences > Security and Privacy
On the left pane:
If you can not make any change, please click the lock on bottom left to unlock before making changes