What is up with KawaiiStacie’s Mods always breaking and never updating?

I would say play offline to avoid patching for as long as you can... but I don't know if the new EA app let's you keep updates at bay like Origin does.

I give it a few days for patching if I'm that eager to play with the newest update. Make note of broken mods before removing them and update the rest. I only download from creators who are active. Taking months to update mods is not what I consider active. It's understandable to be busy with RL of course.

Also you mentioned ruined save files. I highly recommend making a habit of backing up your game files. It will save you plenty of grief down the road.