Well I'll be a...
As I said above, I personally sat in front of a machine the other day, tweaked the registry using the instructions on the linked page and the upgrade worked, despite the CPU being unsupported.
Today, I am holding in my hand the same device I read those instructions on. Not only has the link I followed (via the page: "Ways to install Windows 11" ) gone, but the history of my having visited the page with the instructions (more than once) has upped and vanished from Edge on Android (that'll teach me).
Were it not for the fact that I still have the upgraded machine, I'd suspect that I'd dreamed it all....
EDIT: The tweak was to add the REG_DWORD AllowUpgradesWithUnsupportedTPMorCPU to the key HKLM\SYSTEM\Setup\MoSetup and set it to "1". Anyone want to check if that still works?
Yup. Evidence still there in the machine's registry. I'm not dreaming this at all.