Magic moving a typical physical force or object doesn't change the obect of force... Unless if a typical force or object is being enhanced by magic that it changes the nature of that object or forces "aura" just like Superman's "aura" protects his earth made uniform making it as strong as he is or the flashes aura protects him and his uniform form friction which should melt any speedster into gel.
1. Post crisis, (prezero hour?) all the kryptonians were genetically locked tot he planet for some reason. This had been the status quo for so many millennia, that they forgot about it when they started up their space program again and several thousand colonists died as their ship left the atmospheric boundary. If the Guardians didn't work around this, because they couldn't be stuffed, that would mean that any kryptonian was given the power of spaceflight would immediately die if they edged a freckle too far form the planets surface.
2. A Kryptonian can move and think and react at relativistic speeds. Just the same as if Barry Allen had had a Green Lantern Ring and he could create half a billion deadly constructs rushing towards endgame and checkmate picosecopnds after he'd decided to destroy the opposition.