TIL-Lab49/Mute your microphone with a global keyboard shortcut.

00.guide.md

You could create your own quick action in Automator with Applescript, which is certainly fun. Here's a great guide for doing that: https://medium.com/macoclock/how-in-the-bleep-do-i-mute-my-mic-anywhere-on-macos-d2fa1185b13 (and a preview of the Applescript below).

However, there is a big limitation in that you don't get any visual feedback if your input channel is muted. Instead, you could just install Mutify, which gives you a global hotkey and a taskbar icon.

01.applescript.applescript

on getMicrophoneVolume()
  input volume of (get volume settings)
end getMicrophoneVolume
on disableMicrophone()
  set volume input volume 0
end disableMicrophone
on enableMicrophone()
  set volume input volume 100
end enableMicrophone

if getMicrophoneVolume() is greater than 0 then
  disableMicrophone()
else
  enableMicrophone()
end if