So, I don’t have personal knowledge of this but in reading out of curiosity this seems to be related to privacy policies specific to those browsers but I’m also seeing that using “allow” should work in this case so long as there is no more restrictive policy overriding.
Have you tried microphone *?
Would you mind posting what the html looks like once it’s rendered?
Also is it possible to get any error/console logging specific to mobile in your case?