I think this might need a bit more time. The final volume just tried to resolve too many plot points at the same time.
First the confession, then the MC grappling with whether he likes boys or not, then dealing with the falling out of the MC not liking boys, then MC trying to rever their relationship to friendship status because he cares about gender, then the trap MC dealing with their own internal conflict sland fear of rejection, and finally the resolution.
This was all way to much for one volume, and I think the audience in the play being disinterested is supposed to symbolize something, but I cant figure out what