I know I shouldn't be using Google Meet. Terrible option. But work requires, and I use containers to mitigate risk.
What specific setting causes hardened Firefox not to work well with Google Meet?
Most work we tell you to use Zoom. Ask them to setup Zoom instead, or even ask if they can use Jitsi
OpSec I wouldn't trust Zoom with a byte of my data, much less install that shit on my PC. Jitsi looks like a good alternative, but web-based is probably the way to go (keeping it sandboxed and all)
RFP in firefox can be kind of agressive and will break sites. My recommendation is that you install the Add-On "Privacy Settings" which has a quick toggle to disable/enable the resist fingreprinting setting. This way you can turn it off whenever you have to use those services. Don't forget turning it back on after you're done with google meet.