I uninstalled OneDrive from my PC But that was a grave mistake. I nearly lost everything i have, and it fucked up my game too. When i play the game, it will be treated like i just started the game; No mods, no CAS sims, no sub-hoods, yada yada.
Everything else is visible outside of normal Gameplay, and in SimPE. My CAS Sims are hidden and the mods don't work anymore. And my files turn into read only all of the time, and it's probably because i did a grave mistake of hiding my documents, with properties because i am a dumbass.

What do i do?!
I have Sims 2 Ultimate Collection and i run my pc on Windows 11

Always backup everything (to a location preferably away from the computer, like an external harddrive/thumbdrive/similar) before doing changes like that. Always.

If OneDrive is affecting the Documents folder, it can and probably will delete or mess up files in the Documents folder when you attempt to remove it. If it hasn't deleted the files, it most likely did something to the folder path, so the game no longer reads the files properly, at least if the game was tied to the OneDrive path.

Check if this location still exists (either one, depends on game version) - "name" is the name of the computer:
C:\Users\NAME\Documents\EA Games\The Sims™ 2 Ultimate Collection
C:\Users\NAME\Documents\EA Games\The Sims 2

It's possible your computer regenerated the folder when you ran your game after removing OneDrive. In that case, it will have reset everything to "factory settings" (a clean copy of the files in the install location).

It still exists. But once again, my Sims 2 thinks i just downloaded the game, even when i loaded a lot (more specifically the Pleasants Family) it asked me whether i want to enable game tips or not which only occurs if you reset your game tips (which i didn't) or just started playing for the first time

It honestly sounds like your saves are gone. What you're describing is exactly what would happen if the C:/Users/User/Documents/EA Games folder was removed and the game created a new one.