A keyboard shortcut globally mutes and unmutes your microphone, no matter what video conferencing software you are using.
The menu bar will change from green to red accordingly.
When in a meeting I always used the global keyboard shortcut of Zoom to mute e.g. when I'm coughing or talking to someone who just walked in.
But I never really trusted it and double-checked, which kind of was annoying.
So I build a macro that just mutes the microphone system-wide (by using Apple Script).
In this mechanism I had slightly more trust but I still wanted something visual, for that extra peace of mind.
So I changed the desktop background/wallpaper to green or red so that the menu bar is a huge microphone state indicator.
Plus, as soon as Zoom/Skype/Microsoft Teams etc. are quit another macro sets my wallpaper to my default one again.
The path for all the default mac OS wallpaper is: /System/Library/Desktop Pictures
This also works with those new fancy dynamic wallpapers that change based on the time of day, as those are all stored in one file.