Hi Stephen,
I'm Rodrigo and I'll help you.
If you want to disable OneDrive, first ensure to deactivate the backup function (if activated), right-click the OneDrive icon on the right side of the taskbar (Cloud icon) > Settings > Manage Backup > Turn off all options > Close
Now, unlink your Microsoft account, on the OneDrive Settings window, go to Account > Unlink this PC > You will see a message about your files, and online-only files will be removed, they are safe in the cloud. Local files are not affected.
>Unlink account.
To Close OneDrive, right-click the icon on the right side of the taskbar again > Pause syncing > Quit OneDrive.
To disable OneDrive to start with Windows, right-click the Start Menu > Task Manager > Startup apps (4th icon below the 3 lines) > Right-click OneDrive > Disable.
Now you disabled OneDrive and it will not start when you start your computer.