Having the same problem, the fix is to NOT use the default MS account for daily use.
Go into settings\add user and make a new Offline user account, you still have to run the Sims 4 system folders in the main documents folder but it doesn't actually go to MS One Drive.
I even went to the extent of uninstalling One Drive, and still EA\Origin tries to force me to use Cloud Storage for my mods and saves etc.
These corporations are getting out of hand when it comes to our rights in our own homes on our own PC's.
