I'm playing on 20w11a myself, but i don't see any other bug report about this, but there is a massive drop in framerate and a huge increase in ms-tick when getting close or interacting with my endermen farm. It could possibly be the Enderman AI. It's not the amount of entities because my game functioned perfectly in the beginning of using the farm, but gradually changed into a lag frenzy. We now have a disposal system but that doesn't change a thing. Now i can't even get close to my farm anymore without hitting 0 FPS. Even high end gaming pc's couldn't get more than 0 FPS and our server overflowed because of it.