I also read The Left Hand of Darkness this year! I remember her going out of her way to be like "the Gethens definitely aren't male or female, but we only have gendered pronouns in English, sucks to suck," but maybe that was the introduction of the version I have, or maybe I'm misremembering. It is kind of wild that no one tried to make singular they more of a thing earlier.
Anyway, more power to the protagonist of Ancillary Justice coming from a society that uses she for everyone, walking into a bar where they still have two gendered pronouns, being like "god, it's so hard to remember which is which, and they get so pissy when you get it wrong," and then winning the bar fight that breaks out when she fucks it up.
In conclusion, this is my favorite joke I've written in years:
Me trying to come out as nonbinary: "I'm something of a Gethen myself"
My friends: "getting laid at most once a month?"