@LausCassidy It's possible that the content on OneDrive includes the newer versions of your saves; the only way to find out is to open them and look. First though, disable OneDrive's auto syncing of Documents:
https://support.microsoft.com/en-us/office/choose-which-onedrive-folders-to-sync-to-your-computer-98b8b011-8b94-419b-aa95-a14ff2415e85
This will keep OneDrive running, so you can retrieve content from it, but will prevent it from moving your files around on its own. When you're satisfied, you can uninstall or just disable it if you want.
Move the Sims 4 folder out of OneDrive and onto your desktop and look at the saves and Tray folders inside. You'll get some idea of what they are from their modified dates, that is if moving the files doesn't reset the dates. If you want to load the files in-game, go into the Sims 4 folder in Documents\Electronic Arts and move the saves and Tray files to the desktop (not in the same location as the ones from OneDrive; create a new folder if necessary), and move the ones from OneDrive into that Sims 4 folder. When you load the game, you'll see all the OneDrive content.
If the saves and tray files don't load, it might be because of how they're named. Saves in particular need to be named in the format Slot_0000000x.save , so if there are extra numbers in there, e.g. Slot_0000000x 2.save, the game won't read them. You can just remove the extraneous numbers though.