You’re basically asking what I would like to see in a book. Because visual novels have more in common with books than with gameplay-oriented games.
To answer the question: when I read fiction purely for enjoyment, I usually read fantasy. Fantasy that takes its world seriously, not rpg-verse parodies or isekai power fantasies. Something along the lines of Lord of the Rings or The Earthsea cycle. With the added visuals of a visual novel, but without all of the compromises involved in a TV/movie adaption.
Wait, I just noticed that you’re one of those AI “developers”. I don’t want anything from you. I’m leaving my reply up in case someone else finds it interesting, but I’m blocking you now, so don’t bother responding.