I also think there would still be trans people, but no gender (splitting hairs here). People would still be dysphoric about their body (not necessarily parts, but also processes), but that would not necessarily be related to a gender. A person could of course choose a gender, they’re not outlawed in my ideal post sexism world, but it’s kind of like identifying as a jock or a drama kid after high school: it would be fucked up for someone else to assume it of you, but feel free to identify with it. If you do, you might have to explain to others what it means.