There is a test site at
https://zoom.us/testI found it working from Debian / Firefox 78 on an x86 system
Using Debian / Firefox 78 on ppc64le, it gives the error about audio not being supported
I installed the User-Agent switcher plugin on the ppc64le system and tried changing the UA string to include x86_64, pretending to be x86. This didn't work.
If JavaScript code checks the User-Agent (UA) string, does the User-Agent switcher plugin intervene correctly?
Is there anything else Zoom could be checking?