To be honest, Kanou and Matsukata both deserves to be with Kobayakawa. Alas, this type of romance manga won't end up in harem ending. Rather, they would sometimes end in open ending or with the first girl. However, he needs to realize himself that debt he owes to Kanou is already now in the past and he no longer needs to dwell on it too much.
Kanou's character development is pretty interesting. She might have an idea as to how their relationship will turn out. Kobayakawa is still hunted by his past and Kanou's trying her best to make Kobakayawa to let go of it. Still, will it be too late for Kobakayawa to realize it? Or will he forgive himself? Hopefully he will. For his very own happiness and to Kanou. Damn. I'm getting sentimental over a fiction lmao.
Nevertheless, will the author has the balls to change this kinds of trope into the other way? Or will it just be the same manga with different characters? Hopefully it will be the former. As I don't how or why will Kobayakawa will have feelings for the first girl. But I guess with that kind of interaction, he will have some kind of feelings toward her eventually. Whether he realize it or not.