use the web app. if you can't, put them in a different user profile that you only use when you need to use these trash apps

I don't use any of these apps, for years now, but if these can do it, others could as well, and maybe some that I'm using, even if I try to minimize the shitty closed source app, some are hard to replace.

yep, same advice applies. use webapp where possible, separate profile for others

In GrapheneOS you control what permissions you give to apps. If you decide against them having microphone access you can rest assured that they won't have it.