Obviously the manga won't go there .... but what if. WHAT IF. She succeed in her goal and her feelings did fade away. She feels no romantic feelings to MC, not even in far future. And seeing her disinterest, Keisuke simply moves on. They keep their friendship, push each other to be more social and remove bad aspects of themselves and we go to a friendship ending. If they have romantic adventure, it would be another character, and Kusonoki and Keisuke would try to help each other up if need be. Pure friendship manga, and the romantic side is treated as side goal of growing up. I don't care much about the snake girl, even if there's a plot where Keisuke help her or something, Moe is fine I guess but Keisuke isn't really that interested.
Fanfiction aside, it was interesting to see Kusonoki try to question her feelings via AI, it's very much a thing now and it's not a SCI FI stuff, so manga integrating in the story is normal I guess. If there's any question, just ask AI, it's easy to do and may change the dynamics of kids/teens growing up. AI isn't perfect but you can spend time conversing with any topic and can give you a lot to think about.