I used Camo to do this on my Macbook, but I don't know if there's a Linux alternative. Iriun Webcam (https://iriun.com/) works but doesn't seem to pass on the audio from the mic.
It's worth noting it might be working but I can't actually select it in any program.
good , that is the first time i hear about that app(iriun), i have used droidcam instead of it, but i have a lot of problem with droidcam, I'm trying iriun app now, it's good until now. mic is working me now in iriun, just i choise alsa loopback,
to get mic work with it , i have followed tip in doridcam,
i have run that command in terminal: pacmd load-module module-alsa-source source_properties=device.description=Iriun device=hw:Loopback,1,0
u can read that in doridcam(read from sound support) https://www.dev47apps.com/droidcam/linux/
and i go to icon of sound in the panel and check that:
u have problem with mic generally, or only with that app?
I'm using zorin lite which use volume control(pavucontrol).
I also don't know if u have choice Iriun to be the mic as i did in the pic two(zorin lite), and how u test the mic? u used recorder app to test that?
if u have problem with mic in general, i think others helpful people here which have more knowledge in the community will help u.
there is link for sound and mic problem from the official site of zorin: