There are plenty of examples of protagonists who are sociopaths or psychopaths:
From Dexter the mass murderer who investigates his own crimes, to Villanelle in Killing Eve who is both protagonist and antagonist depending on the moment, to Amos Burton on The Expanse who is a sociopath who experiences dissonance when he realises his sociopathy, to Patrick Bateman of American Psycho who is aware of his psychopathy and again experiences dissonance but then finally acceptance.
These films depend on us not being sociopaths. We experience sympathy for the characters who's lack of empathy itself becomes a weakness that tugs at our heart strings. They are the protagonists literally because they are sociopaths.
So I think this is the wrong tree to bark up. The real key to the sociopath/psychopath villain relationship is subjective. Like all other villains.