Just seems unfair to pin how he turned out on Yuwon. Dohun already shown signs of having apathy at the playground. The biggest factor in why he is the way he is now, I believe lie way before he even met Yuwon. I thought it was bc of his mothers neglect and her abandoning him? From the moment they met he already had a twisted outlook on happiness but makes a wish for Yuwon’s unhappiness to be his. Yuwon in all this was just a random unsuspecting kid who acted before thinking and was forced to play a part in Dohun’s story.
As for Dohun’s ability to adapt and his good sense in people that’s expected considering their career he also spent 13 years preparing to take over the company. I do find it interesting how he navigates work place conflict with ease like you mentioned I guess he does have the potential to be a normal guy with apathy. Yet when dealing with Yuwon he intentionally keeps him in the dark. He only uses his happiness as a mask to conceal his own selfish desires. He benefits the most from the very things people call Yuwon schizophrenic for: his uncertainty, doubts, distorted memory gaps, paranoia, vivid hallucinations. Dohun only further feeds the confusion by not being honest, pushing a narrative that nobody likes him and telling him that he should stay home bc only he can make him happy. He is trying to establish a codependent relationship where he is both the “cause and relief” of Yuwon’s misfortunes to ensure he wouldn’t be able to live without his hand which I think was the actual intent of his wish all along.
To make long story short I find Dohun wanting Yuwon’s misfortunes was for his own advantage, to build control. He’ll later fuel Yuwon’s delusions and violent behavior in an attempt to keep him by his side forever. Pushing blame on Yuwon makes no sense to me when Dohun was the one to lay the traps.

Man.. I feel like dohun/ML could have been normal or at least pretend to be if everyone around him wasn’t batshit crazy ‘lost a lot of marbles’ kinda people. Because unlike everyone else, I feel like his general apathy towards people and ability to adapt is what keeps him grounded and able to get a good sense of the people around him.
If his dad never taught him those terrible life lessons he learned (as another child with low empathy) and if the man he was obsessed with wasn’t full on schizophrenic and ignorant to the abuse around him, he could have been normal; just a real apathetic fellow.