Before update 1.16.100 my realms and single player worlds were relatively lag free, but now combat is not an option. The biggest issue I have right now is that my villagers disappear. If I'm around when they go to bed they glitch through the walls and vanish, and sometimes when I go to my villagers some of them are gone, but when I restart minecraft they come back. BUT, when they try to sleep they move horizontally in their sleeping position and go through the wall and vanish for good. Really frustrating since I had mending, unbreaking III, sharpness V, and silk touch librarians and now they're all gone... and I never had this issue before the update, I never lost one.