OK, so I did the purge, restarted PC. Then Windows Update did a few minor updates, so rebooted PC after them.
After this, I am now showing the Windows 11 upgrade as "Coming soon: Windows 11, version 22H2". apparently I'm now in some sort of holding pattern.
I will wait and check this every day to see if this changes. I think this is progress?

Following the "Learn more" link, I see this:
