Run slui.exe /upk. This is not always necessary but I suspect sometimes the Home license will be installed and needs to be removed first. Doesn't hurt to do anyway.
Run changepk.exe /ProductKey <Your product Key> It will say it failed but ignore it.
Restart
It's now Windows 11 Pro.
changepk.exe /ProductKey VK7JG-NPHTM-C97JM-9MPGT-3V66T