The best two are Chrome and Firefox, especially Chrome since it has more features on the screenshare side and on desktop. Right now I can't make any guarantees about Brave, some have said it works others said it doesn't. Your operating system also matters, desktop or mobile, and if you can give highly specific details "on whose mic and on in what situation" exactly, then we can be of better assistance or just tell @ButtercupRoberts when you're in a testing room.
