Eh Firefox doesn't work fine with at least Google Meet in my experience (which covers both Firefox on macOS aarch64 and Firefox on Linux amd64). It's alright in the beginning, but if Firefox has been open for a while, the out-going audio gets choppy and the recipients don't hear anything. Restarting Firefox fixes it, but this is enough of a problem for me to have Chrome installed on every computer where I may have to do a video call.
Firefox doesn't seem to be intentionally blocked by Teams in my experience (or at least not anymore?), but maybe it should be.
I haven't had that experience, but then when it comes to audio there can be so many e.g. device (hardware+various OS parts) specific issues that only some of the browsers might have workarounds for that it's quite viable (but AFIK not the norm, and not limited to works on Chrom but not Firefox, the other way around is possible too).
Either way it doesn't matter much because:
- jitsi meet even when they still was a small startup managed to provide high quality video calling on all browsers/platforms
- MS Teams has more then enough resource to make things work, they just don't want to (same for properly maintaining their Linux app, which given that it can be a local deploy of the web-app a very little other code could be a 1.5 person job (the +.5 person in case the first is sick)) and have a good reason not to (they have been pushing edge hard, including using inappropriate means like deceiving windows users into using it when they clearly signaled they want to use another browser)
You're right that when it comes to audio, there can be hardware + OS specific issues. But we're talking systems as different as aarch64 MacBook Pro running macOS with built-in mic and speakers on one hand a amd64 desktop running Ubuntu with a USB headset on the other hand both consistently exhibiting the exact same issue, but only in Firefox (not Chrome, not Discord, not TeamSpeak). My money's on that being a Firefox issue.
And the issue in Firefox across both those wildly different systems is present in Microsoft Teams, Google Meet and (I believe) Slack's Huddle.
Microsoft has the resources to make it work, sure, but I'm betting "making it work" here means fixing the issue in Firefox.
I've used Firefox on Linux to regularly attend multi-hour meetings for the last at least 5 years without issues from multiple devices and it has always worked smoothly for me. The only issue I have had is that in the last year sometimes the joining screen says that I have no camera and mic for a while (maybe 20s) before letting me join.
I regularly use Meet, Zoom and Jitsi on Firefox and Meet has been the only one that always just worked for me and my guests.
Firefox doesn't seem to be intentionally blocked by Teams in my experience (or at least not anymore?), but maybe it should be.