The magic weakness almost always comes into play when someone is casting spells at Superman, particularly if they are not just magical blasts.
That said, the degree of weakness is pretty random, and Superman has overcome many magic users.
Putting 'morals off' doesn't make it more likely that Superman would use super speed or anything like that. But it does make a dynamic power portrayal more likely, though by no means inevitable. So there's a greater chance you sill a Superman who is significantly above top tier.
It's tough rating the fight overall. I'm still thinking about it, but these are some of my thoughts thus far.