I keep chromium for Google meet exclusively. I got awful performance on Firefox... not that chrome is much better - but at least I can kill it after every meeting without losing other tabs.
Used Google Meet just yesterday, only a small meeting with five people, but all with webcams and of course audio. Flawless and smooth with Firefox 86 on Windows 10.
I have also noticed better performance on Firefox compared to Chrome. Quite surprising but worth a try. Meet only really works well for small meetings though. Any bigger and it slowly starts to fall apart.
