You could make a villainess isekai about the other female char in this, shes completely just shoved around for the 2 MCs convinience.
Shes even set up as mean for not helping, I mean its obviously not nice to ignore it with bullshit reasoning like that, but that was really the typical villainess thing to do.
Like imagine your friend having a opposite gender friend, just casually you talk with the person, no thoughts like dating or whatnot. Then a bit later the friends friend is comming onto you and being super obvious and your friend is making you meet randomly and prb doing stuff like saying the other persons good points. So you go for like a year like that basically dating your friends friend, maybe even factually dating. And then at the end of the school year the person thats been comming onto you all this time just ends it and goes over to make out with your friend and your friend is like "I actually liked this person from the start, I completely didn't fuck you over and treat you like shit because you two ware never ment to be".
Also yes I made it gender neutral and it was way more effort to type like that.