Hi, the fact is that if you want to build a new computer, with your product key for Windows 10 from an old computer, you can use that on 1 computer, the fear is the upgrade.
Concider Windows 10 as if it is done, and prepare, because if you want to do that, you can install Windows 10 and upgrade to windows 11, but such upgrades give many system problems.
So just use Windows 10, or get the upgrade and you download Windows 11 while you are still running Windows 10, to have the autentification for that product key for Microsoft Windows, just like the license for Cubase, to use Windows 11 clean, never use a system that was UPGRADE from 10 to 11 and install Cubase.
Because you can face many system errors, what after a clean install with the good drivers is not an issue.