I mean, the reason Akagi and the other characters act the way they do is pretty well laid out by the author. Akagi heavily resents Minikagi because she sees the latter as stealing the time and attention of the revived Amagi- AKA the most important person in the world to Akagi who is not the Commander. Akagi is, quite frankly, not the most emotionally stable ship even in the game. So their relationship is poisoned right out the gate, and Akagi makes it worse by refusing to have anything to do with her younger doppelganger.