There are many ways the 'Harem' and 'Romance' tag can be approached in a game. Some ditch everything and just try to win the player over with quantity. Some create uniqueness with the models to appeal to differing tastes visually. Some might weave in elaborate gameplay mechanics to keep the player occupied.
This approach here however is my favorite. Worldbuilding. Making characters relatable, giving them depth. Having them be consistent in their actions throughout.Making the player care for them and wanting to know more about them.
Very few are able to pull this off and I think you are, although I am still not through all of the current content. It's that moment when you realize you might have initially downloaded for the lewd content and now keep playing because you want to see how the characters move forward in their own growth and their interactions with everyone else.
Well done.