Jack Torrance.

MCU red skull isn't played up to the same level of insanity as homelander, bates, Hannibal lector and Bateman. Homelander, Norman Bates, Patrick Bateman and Hannibal Lector are definitely psychopaths but if we're talking about who's the most insane I would have to give it to Jack Torrence. Just watch the shining and see what I mean

Now this is tough.

I think Homelander and Bateman are equally insane, although Homelander is more tragic.

Professor Pyg dc

if we're speaking in terms of psychopathy, Red Skull has them all beat. He's practically evil incarnate

Insanity goes to Jack Torrance. But Psychopathy definitely goes to Red Skull. Because he is a pure evil psychopath