Works fine for me. I also took a zoom call from Firefox just yesterday (153.0b13 on mac). So, I think this is false alarm.

I also see no good reason why Zoom would want to restrict this. Likewise, I don't see them dropping support for Safari either (works fine as well).

Maybe they limit things on mobile? But on IOS they'd be stuck having to support the Safari browser engine anyway as neither the Chrome nor Firefox browser engines are used on that platform (both browser delegate to Apple's browser engine there).