Sims keep freezing

For several months, my sims will freeze and just stand there for several in-game hours  while the world around them passes by like normal. Then, when they unfreeze, they will cancel whatever actions I commanded them to do. It's becoming increasingly frustrating. I do not play with mods or custom content, I have repaired my game multiple times. Sometimes, even when they aren't freezing, they just flat out won't do what I command of them for no reason. I also noticed the autonomous function has been lacking. Even NPC's just stand around doing nothing. I haven't disabled autonomy in my settings at all.