Hi Arthur,
My name is Igor, it's a pleasure for me to help others and I'll do all my best to help you.
When you try to upgrade Home to Pro thru Store, the Store does not check if you purchased an upgrade previously, it just suggests a new upgrade.
Do you mean you have Windows 11 Home after reinstallation? If yes, please change a product key to a generic Pro key: VK7JG-NPHTM-C97JM-9MPGT-3V66T This should help.