Depends on your last check-in, if you have checked in it might be OK.
In that case… try this but take care
Move all your Projects from your current Projects Folder on OneDrive to somewhere UEFN can’t see them.
Make an empty Projects Folder outside of One Drive
Go into UEFN and create a new project (ignore your files) just to get to the Edit menu Edit Preferences and add a new Projects Folder pointing to your new empty folder.
Exit
Now you can either…
Reload UEFN and hopefully you’ll have the option to download your projects, if you have been checking in often.
Or if you don’t check in changes much, try copying your moved project files to the new folder then load UEFN and hope they work from there.