All File Change Dates changed

I activated virtual file support on my nextcloud Client, then quickly deactivated it, as he tried to sync a lot stuff which i was afraid of. Now he almost touched every folder in Nextcloud and changed the “Changed last” Date of my stuff.
Does anyone know, why this happened and if there were any files harmed/deleted or if i can change it back. What was synced? Before Client and Cloud were synced except the big files.
I hope my Problem is understandable, as English is not my native Language.
Best regards and thanks!