Would a bit of Post-It Note (for minimal adhesion) damage the screen coating if left on most of the time? Would even that much thickness stress the screen when opened and closed thousands of times? Is there a better (self-service) material?

Plastic slide covers that stick on are pretty cheap if your laptop doesn't already have one. I also think that the open microphone issue is a greater problem, especially with the current ability of speech-to-text, but what you utter may not be as important as being seen "doing a Toobin" during an online meeting. YMMV :) (I won't expand that acronym!)

> Would a bit of Post-It Note (for minimal adhesion) damage the screen coating if left on most of the time?

Possible, I have one IPS monitor with a spot on screen where the color is pale. I had a post-it note there and I guess something bad happened when I tore it off.