Windows 10 product key not working on Windows 11

If your Windows 10 product key is not working on Windows 11, check the Windows Edition, your activation status, and then ...
Ars Technica

Microsoft will stop old Windows product keys from activating new Windows installs

At least for now, though, it seems like this change will only apply to future Windows versions. We were able to activate a fresh Windows 11 Pro 22H2 install with a Windows 8 Pro product key as of this ...