Curry is a better shooter, better ballhandler, better penetrator and layup package on drives, better defender of other point guards.
Magic is the better passer, better rebounder, better scorer out of the post, better defender of bigger players.
It's a weird argument because their skill sets are so different that they barely play the same position. It's easier to compare Curry to shooting guards than to compare him to point guards, and even harder to compare him to Magic who was a weird-ass point guard almost to the point of being a point forward (cause he didn't break guys down off the dribble and didn't defend point guards on the other end).
Overall as players, Magic has the better argument for GOAT career because of his MVPs and Finals MVPs. But it's entirely subjective to speak on who the better player is.