That's exactly how it currently works, though. Different states can and do set different healthcare standards, above some minimum floor.

I'm not sure why you think there's a problem with that. (I mean, I think it's a problem for the residents of a lot of states, but that's their problem, that they have agency to fix, not mine.)

If the Midwest likes using paint chips as food coloring, that's not my problem. And it should still not be my problem if they elect some brain-worm addled moron to a federal office who goes and raises the federally permitted amount of paint in my food.