@SuperOniichan IIRC, Oshimi said in some interview that his next manga was going to try and tackle a serious topic, so I don't get the impression he's taking the subject flippantly. Whether or not he'll succeed in doing something that isn't gross is another matter.
@mirewitch This translation is really janky. Reading the raws, it seems more like she's saying "I was once a boy, but it wasn't for me" in kind of a flippant way.
There's also a really specific trans flag colours reference in the second page of the first chapter, but that could be...