People in the notes saying “oh this is het this is yuri” You aren’t seeing the plot here.

Guy and girl are dating. Guy is inspired to make a band with a close friend of his and writes songs about the girl. The music career threatens his relationship with the girl he’s dating. The girlfriend breaks up with the guy. The band dissolves. The girl starts a new relationship with the close friend. The close friend comes out as a trans man (whom the guy shamefully experiences as an ex-girl). The new guy ends up being way better at writing music than the first guy and becomes very successful. The first guy has to grapple with the realization that he was actually in the band to begin with not for the girl he was ostensibly dating but to hang out with the new guy he didn’t know he needed in his life instead. He will struggle with internalized homophobia and transphobia about it, but the story ends before we know how that turns out.

That’s an interpretation i can see, anyway.