..

He already admitted he's a high-spec dude who's always excelled at whatever he's done maybe for him it's worth being a sultan if he could keep the one person who cared for him without asking for recompense by his side

Yeah but being in a job you aren't exclusively interested in is miserable. Tons of people quit halfway to pursue what they love halfway and he can't do that Because He's King. Also being good and swordfighting or studies is Very Very different from being a good King. You have to have strong leader qualities (and that's not just being an Alpha male jerk you have to learn how to lead and motivate people at the same time or else that impacts productivity) as well as a good sense of judgement and moral compass, generosity but also knowing when to stop and a hundred different things and over everything, a love for the people, and respect for the citizens and the people you work alongside. This isn't stuff you just learn or are born with this is stuff you have to constantly strive for.

I agree that high skills = good leader but even if he wasn't interested in ruling doesn't mean he's not well-equipped to be one, having been raised a prince.

Plus, monarchs in absolute monarchies in the middle ages didn't need to be loved by their people nor did they need to listen to them (democracy who?) + they delegated everything to ministers anyway. He's only accountable to himself and to whichever deity he believes in.

Anyway, it's a bodice ripper and I'm just here for the sexytimes.

Sexytimes we shall enjoy.