Okay, I definitely agree with you on the player being the only romance option for NPCs... for the most part. Looking at it, I do see plenty of existing romances in Skyrim, Fallout 4, and Cyberpunk 2077 — the examples I gave — and I think they're mostly straight. In Cyberpunk, Judy Alvarez, an established lesbian character who will only romance you if you're female, has a female ex who is a main character. You meet her before you meet Judy. She's the one who gets you the heist gig, sort of. The one who hires Dex, who hires you and Jackie. It may not be obvious at first, but if you follow Judy's story, even as a male character, it will be obvious. And Fallout 4 had a romance with two robots, but that's mainly played for laughs and most people will never see it. (You have to go to the school in Diamond City and speak with the female robot, who will ask you about love. Give the most heartfelt answer and, the next night, you will see her wed a male robot outside the all-faith chapel, if you're there for it — you could be elsewhere and you will miss it.) But that's a robot relationship, and it's hetero.

I do want to say one or two of them had a couple gay/lesbian romances.

Going a bit off-topic, Animal Crossing — largely considered a kids' game — actually has a bunch of stuff just beneath the surface that most people will overlook. Flick, the bug collector, is considered by many fans to be FTM trans. He identifies as male but appears to be AFAB. There's a peacock who identifies as female — peacocks are specifically the male of the peafowl species. Peahens are the females, and they don't have the big feathery thing. So that's a female character who was AMAB. Plenty of other characters rock the trans flag as well. Kids would never notice this, and being a Japanese game, they have to be very careful as that country is super conservative. (There's actually a pretty deep rabbit hole on that game's lore. Some characters hint toward the game being a game, breaking the fourth wall. There are also hints the game takes place in a post-apocalyptic world and you're the last human.)

I'm with you though, in that I would like to see more same-sex relationships and LGBTQ+ representation in my games.