This game only has male LIs. Cove, Derek and Baxter will always be the only romance options. You're allowed to be attracted to more genders than that since there's no reason to erase someone's full spectrum of preferences, even if in this situation they've chosen to pursue a guy, and because there are many people who don't like guys at all who play the
game purely for wholesome friendships.
Cove is the only lead romance option of the game, there wasn't a way to fit someone else into the story who had equal time/attention. It would've been insulting to make a female or non-binary LI who was second fiddle to Cove. So, the side LIs are the same gender as him and OL: B&A is a dude friendship/romance sim. It was either that or have no side options at all. We're just weren't gonna ask people who like other genders to play this game because we threw them a small bone.
Our Life: Now & Forever is the game that's for lady and non-binary love interests. You can read the basic details HERE.