Walking Practice by Dolki Min
It's a weird fuckin book. I don't regret reading it, but i don't think I liked it. It's ... interesting? Idunno man. I probably wouldn't have finished it but it was REALLY short. I think it's worth a try, at least.
I was seeking out a book that featured non-binary characters because I am non-binary and haven't seen my kind represented in fictional books I've read. This did not particularly satisfy my desire to see myself represented, but I appreciated some of the commentary on gender.
For a different (and very good) book that casually features some non-binary characters, see Black Sun by Rebecca Roanhorse
This book is, in part, a commentary on gender. The alien's race does not have fixed genders, and the alien can be either male or female human, depending what date they've setup. They play a straight human at times, and a gay human at others.
The commentary revolves around feeling out of place in the world as a queer person, and wanting to find others like you. This is written by Dolki Min, a South Korean, who wanted to bring forward queer media in the face of threats to the LGBTQIA+ community. This book is a translation of Dolki Min's original.
Below, I spoil the central plot of the book, but not the outcome. You learn the main plot pretty early on.
The main character is an Alien who's (crash?)landed on earth and who's regular form is quite monstrous by human standards. They can shapeshift and take the form of a person, which they do each day before they go out to hunt. Their method of hunting is to setup dates on a dating app, have sex, and kill their prey right after orgasm. They eat humans.
There is a lot of grueling detail about how hard it is for them to walk, and to simply hold themselves in human form. It's quite the struggle.