Disable Manage folder backup feature in OneDrive settings -> Backup -> Manage backup -> Stop backup on all folders, or toggle them off on newer version.
Try to uncheck "Suggest ways I can finish setting up my device to get the most out of Windows"/"Show me the Windows welcome experience after updates and occasionally when I sign in to highlight what’s new and suggested" in Settings -> System -> Notification & actions (Windows 10) or "Offer suggestions on how I can set up my device" in Settings -> System -> Notifications (Windows 11)
Beat me to it