It's been so long since I've read this. But to put in my two cents - yes he does love him, loads actually. At first he's focused on the idea of having a puppet king, but it changes as his feelings develop towards having Wolfgang be in the safest position possible - because he loves him.
He "rejects" him because he feels he shouldn't want or love Wofgang and only be focused on supporting the kingdom. He doesn't perceive himself as the correct partner for the king. But the reality is he can't help it and loves Woldgang regardless.
do you think reading kings maker shonen-ai version will help me see how he loves him? since it is another story of before he became king
Oh yeah, its fundamental haha! The story is plot driven and the characters are complex, you're missing out on the bulk of the story when you start with a sequel :)
does black haired guy even love Wolfgang? I feel like he's just obsessed with the idea of perfect king and that's it... he's also constantly rejecting him so the smut is not even enjoyable... makes me not want to read it