Disney movies with a romance, like "Mulan" or "Beauty and the Beast," do not teach kids about sex.
If you show the exact same romance but with two same-sex characters, it will ALSO not teach kids about sex.
Saying "queer people exist" is not "teaching kids about sex."
Many more books about queer people, along with content notes, available here: https://ladyrowyn.com/
If you're interested in stories about queer people, I have written many of them! Although they're not aimed at kids and some of them do have explicit sex scenes.
But this one, for example, is also not gonna teach anyone about sex.
https://books2read.com/level99