A Microsoft file hosting and synchronization service.
Dear Marco,
Thanks for writing back and updating with us. Apologies for the delay in the response.
IMO, the temp files will be created when you are working with the Office file on the Office apps, where these temp files will be deleted automatically after save the Office file and these temp files will be helpful during the sudden power outage or unexpected shutdown of Office apps, where it will help to recover the data which is not saved.
Moreover, OneDrive synced folder will not have two files with the same name and if the files are with the different name but the same content, then there won’t be any issue. However, if you are having the sync issues because of the temp files, you can manually remove those temp files and reset your OneDrive sync client: Reset OneDrive - Microsoft Support
If there is any misunderstanding from our end, we apologize and request you to share more details with some screenshots of the problem which will help us to better understand and guide you further.
Appreciate your patience and understanding with us. Have a good weekend ahead!!
Best Regards,
Sophia