Lot doesn't load

I've been having this same problem for a couple of months now. It happened spontaneously on one lot only. It happened after playing this lot for hundreds of hours with the same family (originally the landgraab house in windermere). It's one of the only 64x64 lots in windenburg so I'm super sad about this!

It started one day when I noticed that in the back yard I could see down to the basement. even with all walls up. It was like a big long hole in the yard (try to follow me here)

Annoying but nbd. The first thing I tried was moving my sims to another lot. However when I went to choose to "keep furniture", it said "this household has no furniture" so I knew something was seriously wrong . I ended up putting everything on the lot in the household inventory and moving them that way. With no sims I tried to bulldoze but got the infinity loading screen. Tried to replace with a household from the gallery and got the same loading screen. There is also a build mode issue, I can't delete walls or fences. I read somewhere that it may have to do with the fences, but couldn't figure out a solution. Is there anything that can be done about this? I mean, other than deleting my save file LOL

I have repaired the game a few times. This issue doesn't change when I disable mods and cc