Superman is the one capeshit hero who shouldn't be dark and edgy. Batman is one who should. Superman's primary vulnerability is how much he cares about human life. That's worse than Kryptonite to him, but it's what makes him an actual hero.
Also to revisit the "two sides of the same coin" bullshit, that came from the Joker. That's how he thinks. He's wrong, though, and one of the best moments in the Christopher Nolan Batman movies is the one with the two boats, one full of criminals and the other full of outstanding citizens, and he gave both of them detonators to blow up the other boat. Sort of a mutant capeshit version of shit like the trolley problem that never happens in reality.
Both of them refused. A criminal actually chucked the detonator overboard.
Batman's view turned out right. The Joker is fucked in the head.