I got an email from a good friend on the WDK team just a few minutes ago.
Guess what? After much discussion, the old WDKs are back online:
Unsupported WDK versions - Windows drivers | Microsoft Learn
This is a change that we here at OSR, and so many other members of the community, have been advocating since the WDKs started disappearing some time ago.
And now… they’re back!
THANK YOU MSFT in general, and the WDK Team in particular. This is a VERY positive step and VERY good news for every third party dev who writes or supports Windows drivers.