I have tried 2 plug & play USB webcams since installing Zorin OS 18. When using Google Meet in Chrome, the camera works, but not the mic. Sometimes it seems like it wants to work for a few seconds then goes dead. But mostly I get nothing at all.
I downloaded PulseAudio by recommendation but that hasn't helped. I wouldn't know what to do with it anyway.
If I plug in a USB headset with mic, that works just fine. I'm at a loss.
I'm not sure what can help you.
You could run
alsamixer
and take a look there at microphone. With F6 you can select the soundcard. Make sure microphone is not muted (MM).
You could install pavucontrol
sudo apt install pavucontrol
to setup input devices.
How is chrome browser installed? If it is a flatpak it may help to install flatseal and in flatseal set the permissions for chrome to grant access to all system files. Maybe there is a setting for microphone and camera at tab portals.
Another option that may help is to install the .deb version of chrome if you now use the flatpak version which is better integrated into the system