At least semi relevant is Shush, a mac app that makes toggling OS-wide mute easy, along with push-to-talk (or the inverse, push to mute). I've been a happy user

At least semi relevant is Shush, a mac app that makes toggling OS-wide mute easy, along with push-to-talk (or the inverse, push to mute). I've been a happy user for years. I only wish the menu bar icon were more prominent somehow, or had the option to overlay a floating semi-transparent window that displayed mute status. I'm always paranoid about whether I'm actually muted and wish I could make it glaringly obvious to myself.