Broken Game/Save File???

After the infamous crappy update in August, I built the most beautiful library in the Sims 4, saved it, and it disappeared when I loaded it up the next day. I made it again a few days later, saved a million times before logging out and shutting my game down, but when I came back, it was gone again. I don't know why I didn't just save the lot to the gallery as a precaution, but obviously, I should have expected that all my work would and should load up when I constantly save it.

It showed my library on the Ravenwood world map when I saved it, but when I opened it, it reverted to what it was before I made it a library. I tried to add a few things to another lot while I was playing yesterday, and it wouldn't let me save my lot to the gallery.

I don't know why this is happening. I've tried repairing my game after the update, but that didn't work. Maybe there's an issue with a mod or custom content I have installed? But I have a lot, so I don't know where to start searching.

My laptop is around six years old, and HP Envy x360 with Windows 10. It's about to lose free security updates next month since they're making the big switch to Windows 11. Maybe it's a space or age issue? Because I've been playing the game for as long as I've had this laptop, which my dad gave to me as a graduation present in 2019.

I'm considering getting a new desktop computer by the end of the year because I've been told those are better for gaming, especially The Sims. But I'm unemployed currently and about to get food stamps, so I can't do it at the moment.

I've spent a lot of time and money investing in expanding my game, so I can't afford to just abandon it.

Does anybody have any idea where I can start to fix this issue?