this is a problem with harem/love triangle mangas that contain the main girls name or when the mc instantly falls for the first girl introduced making her the lead. And then they show rivals who are better but have no chance since to the MC's eyes the other was the first.
Though I'm still hoping for a harem end + development with the other girls. It'd suck if it isn't cause he has led on the other girls too much to back down from them.