Yesterady I bought a brand new ASUS F16 gaming laptop without any OS installed. I used Microsoft's official tool to prepare a USB drive for Windows 11 installation. Not sure if this contributed to the issue, but I couldn't see my SSD drive until I disabled VMD via the boot menu (as ASUS support site suggests), then went on with the installation without a product key.
To my surprise, when I wanted to activate Windows via Settings, it claimed "there's been a hardware change", even though I haven't made any changes to hardware. When entering a valid product key through "Change product key" it would just say "Unable to activate windows" (with the same hardware change message showing along), and when opening the store to purchase Windows 11 Home it would say "we couldn't make your copy of windows genuine".
To sum it up: New laptop with fresh Windows 11 home installation, but no way to activate/purchase via the settings UI.