The below worked for me. I was only trying to use my mic (no webcam installed on my PC) and getting the hardware message. As I had (new) Edge installed, I tried that and it still didn't work - which made me lead to think it was Chromium based. Installed Firefox, but wasn't able to join the call, maybe due to it being multi-person.
TLDR:
Click on the padlock next to the site URL whilst on messenger.com
Click "Site Settings"
Click "Reset permissions" (all my settings were on "Ask" and resetting the permissions didn't change anything)
Go back to the messenger.com tab, and the page should ask to reload.
Make/join a call.
The permissions didn't change when I clicked reset, but it fixed it for me. Maybe some permissions left over from previous versions of Chrome were conflicting.
Hope this works for someone else.
