If you could make a non-linux OS go mainstream, which one would you pick?
I make the specification of non-linux because otherwise this would just become a thread full of obscure distros that do the same thing as a million other distros.
Some lesser known OSs:
AROS - based on Amiga OS, has some derivatives like IcarOS and MorphOS
Refox OS. I know today isnt a magic bullet but it makes committing memory mistakes a lot harder. Also rust gets first class status as the is standard library calls it and we can slowly get over the legacy of C.