Well I’d say that for a person to be evil they’d need to be doing evil things with the sole intention of causing harm with nothing good coming out of it. Perhaps a good caricature of an evil person would be someone wanting to destroy the world including themselves. Admittedly such people absolutely does exists so maybe that debunks my own claim.
However if someone draws joy from causing harm to others I wouldn’t still call it evil but more like extreme disregard; you don’t care how others feel, only how it makes you feel. This is why I don’t think billionaires abusing the system for their own benefit makes them evil because causing harm is a byproduct of their selfish goals but not the intention of them. Similarly someone like Hitler wasn’t evil either because causing suffering to the jews was not the reason he set up the death camps but rather a way to achieve his other goals.