Let's just end the simulacra and embrace the absurd, take a video of yourself walking into the room, acting surprised that someone's on a call and awkwardly backing out of the room, if your platform supports animated backgrounds, use it.

Take anyone who notices and asks if you have a previously undisclosed twin-sibling out to dinner for being observant.

Bonus points if you wear the same clothes as your video self to really mess with someone's head

Yeah Apple's network link conditioner is great for this. If you don't want to send video but the organizer insists, just tune it down to the point your audio goes roboty. They'll be begging you to turn off video to improve the connection :D