I think this series is doing a good job of illustrating that not every parent likes who their child is dating. I mean YanMilf is kind of taking it to the extreme by hunting down the boyfriend, which is pretty extreme, but it's understandable that she wants to protect her "pure" teenage daughter. I'm pretty sure it'll blow up in her face, as I've seen happen a lot with my friends growing up. In the end, YanMilf is just like any other parent I've ever seen, with the manga taking a slightly more dramatic approach for the sake of drama probably.
I've honestly forgotten a lot about this series, but maybe after a reread I may be in childhood friend ship. But I like F-cup girl and our MC together and wouldn't be mad if they stayed together. But there seems to be a lot of signals for childhood friend for winner, and based on the "mystery" around her, she definitely seems like endgame for our MC.