Quick Audio Mute / Mute game on loss of focus

I've got the attention span of a goldfish, so I'm constantly switching between 2 or 3 different things at once on my PC. Going into the audio settings menu every 5 minutes is a pain. I would love it if the game would hush when I alt+tab. Or even just a master volume mute button somewhere or hotkey combo would be good enough.

Or maybe program a function key on your keyboard to do this.
If you don't have a mute button on your keyboard, I am sure you could easily do this with Power Toys for Windows 10 or Autohotkey program.
I would think this would be either a very low priority, and/or Not likely.