Is there a shortcut to mute my own audio?
Yes! If you are on a call and would like to mute your audio, just press M on your keyboard. You will see the pink microphone with a slash through it show up in your video showing that you have been muted. To unmute yourself, just click M again.
Caveat: Make sure that the mouse is not in your chat box in the room, or else you'll just be typing M into the chat! :)