Keyboard Shortcuts for Soloing or Muting Audio Tracks/Toggling Output on Video Tracks

I believe they are available now in the beta! 🙂

Have a look here:

https://community.adobe.com/t5/premiere-pro-beta-discussions/now-in-beta-new-commands-for-toggling-track-mute-solo-and-output-in-the-timeline/m-p/15218741

You can set a shortcut for: "Toggle Mute for All Targeted Audio Tracks"

So you can use in combination with CMD+drag on the track selectors (or CTRL + drag in windows) to select your audio tracks and then hit the assigned shortcut to toggle the mute.