Oppossed to me who somehow forgot Copilot is a thing :) Should have realized that.
I have it simply disabled in settings so it does not show up. Maybe it is not completely disabled and some parts of it are still running amd would need to apply policy to disable it, but can't say it bothers me much.
Sounds like a weird behavior, are you using Microsoft account for sign-in? Maybe that somehow triggers enabling sync back. Switch to local account if you do not want any benefits MS account gives.
That OneDrive feature is called Known Folder Move and it can be easily disabled. In theory it's a great feature for most, but I dislike it as well.
I have OneDrive disabled and have never seen it restart automatically.