Nightmaresans500 The user folder is the Sims 4 folder that contains user files like saves and mods. It's in Documents > Electronic Arts > The Sims 4. However, your computer has several Documents folders. Windows designates one as the Documents directory, and Sims 4 tries to use that folder too.
Allowing OneDrive to sync your documents means that OneDrive changes the Documents directory to this:
C:\Users\your username\OneDrive\Documents
Simply disabling OneDrive, or being unable to sign in, does NOT change the location back. So you need to get rid of OneDrive the proper way, as described in the guide I linked.