I recently read a story, and one of the couples in the otherwise bog standard hero fantasy is just casually gay (like, there is no specific mention of it, written like a standard couple, they just happen to both be men). That was great, and I think how it should be normalized.
This is sadly rare and I'd love to know which book/story it was so I can read it, too.
Atm some of the best writing of gay characters I've seen has been Dev/Lee from the books by Kyell Gold. Warning that it is _furry_ fiction, and of course I am biased in this regard, but if you can ignore the fact that all the characters are walking, talking animals, it's a very deep and charming love story with all sorts of fun up and downs (in all senses) and is honestly my favourite book series (even competing with William Gibson's/Neal Stephenson's stuff, which I adore).
Highly recommend reading a snippet/start of "Out of Position" to see if you like it, to anyone that wants a great gay love story.