Hi Oskar,
Welcome to the Microsoft community.
To turn OFF OneDrive syncing go to the OneDrive cloud icon on the taskbar > Settings > "Sync and backup" or Backup > Manage backup. When you are there turn off the sync of all your folders. That will move the system folders back to where they came from. If any files remain in the OneDrive folder you can manually move them back. Then you can uninstall the OneDrive app if you wish.
I hope that helps. Let me know if you need further assistance.
I've been able to turn that off, however there is a problem that yet lingers. Many of these synced programs, games, pictures have not all been successful by OneDrive, during its rundown of synchronizing my things. Many of these programs have made it impossible to transfer from OneDrive to their original spot again. Such errors consists of "being already in another program", or "An unexpected error is keeping you from moving this folder".
The status of these consists of the red cross (the file or folder could not be synced), and the blue cloud icon. These have made a lot of errors to this progress of returning apps and programs. Some of those I successfully got over to the other side, had OneDrive forcefully copied with the status "Processing changes" icon. I could not delete these copies within OneDrive, without having them affect those I pulled/transferred over to their original folder.
Changes usually lag my entire taskbar, refreshes the taskbar, keeps me on a long loading of the programs, to load something that is unknown. Restarting the computer usually fix these loadings, but gets me nowhere. Those files vary from nothing at all (simple document), to a load of pictures and work I've made to have issues being transferred.