Yasashiki
You could add in Harry Potter putting him in as an orphan go to hogwarts as owner of land . His ancestors would have leased out land in magical world pretty have the whole magical world is in debt to him and this unforced by magic leting (take copy whatever you think is more interesting) their magic saved up on land the family talents or their knowledge straight from the brain/soul or you could take the normal stuff enslave them take money everything they have like property or share in a business You could a normal orphan who wants to go up in life or reincarnated dept collector who die but manged to collect a debt in full from a bank who stole trillions from the world and he collected it die as the worlds best debt collector
So I read all of the option if fics,so first of all I live slice-of-life and Harem stories(Not Pokemon Harem ones but the ones that are well done as rare as it is.). So I find two options of my liking 1. Pokemon - as there is lack of good Pokemon fics and I love Pokemon fics and there is Cynthia as love interest ( I think) so why not 2,Overlord - as Overlord is one of my all time favorite anime so I like it,but you said there is no Harem or Romance so a little hesitation. Well lets see what happens in the future.