To keep OneDrive from launching automatically on startup, you can open the Task Manager, go to the Startup Apps tab, and ...
Microsoft is still forcing you to back up your files to the cloud, but recent changes have made it easier to restore your local files. Too bad those changes aren't documented.
In the Sync your settings section, toggle off the settings you do not want to sync. You can choose to disable syncing for theme, passwords, language preferences, Ease ...