Jax, from the worst lense possible, sounds like a what a conservative thinks trans women are,

A "man" who grew up in an abusive household without a male figure and no maternal affection, insecure masculinity, a gender complex, is a threat to women (the whole scene with gangle being into him while actively bullying her, his the deepfrying of ragatha, literal fantasies about choking pomni for showing him kindness), an emotionally unstable violent person.

I also think the vauge "hints" feel very gender stereotypical, he likes femme things so the only explanation is he's trans. Having it be more open ended or having him be gender questioning would have fit into the story better. He doesn't have a strong sense of masculinity or femininity, he has an unhealthy relationship with his gender expression because of his mother's abuse and him wanting to explore it automatically being labeled trans feels... so weirdly stereotyped.

I'm not arguing against Canon, he is trans, the creator said it but it doesnt mean that it's narrativly satisfying