Here is some info on stuffed ear syndrome https://www.soundstagesolo.com/index.php/features/178-eardru...

Mentioned here: https://news.ycombinator.com/item?id=22078517

Not really, but I do get tired of wearing most headphones for prolonger periods... It's also difficult to lay in a pillow to sleep with NC headphones.

Airpods fare a little better, but I'd like something even more improved... if it could somehow let fresh air in and cool my ears a little too, that would be great...

Yes this is a known phenomenon, it's on the rare side but definitely exists. I have it too.