I cleared out disk space today, and popped 1507 into a partition to check it out, used the same video driver # as I am using in 20H2. 1507 sure has a fair bit of UI rough edges compared to 5 years of polishing here and there that has gone into the main line. It's usable, but it didn't leap out at me after I was done tweaking settings. I didn't feel like there was enough of a difference to justify using it compared to something else. It's amazing how busted W10 is.. apparently the March update has busted people's printers. Seems like every month there is a new problem, it's ridiculous. My 20H2 system is still paused at December. I spend almost all my time now in 20H2 instead of 7, which surprises me.
Incidentally, you can slap New Edge on 1507, if you download the installer from MS's Business Downloads page.
Vista w/ extended kernel sounds intriguing, but what's the point if you already have 7? 7 is basically XP to Vista's 2000.
I'll probably try compiling Funtoo in the next couple weeks and see how that goes since I have the partition available now.