Just to preface, I want to make the disclaimer that while I am a queer woman, I am also cis, so I can only say so much about stuff like transfem rep in fiction without speaking over actual trans women. Please do not take my opinions as THE opinions on the subject. Not that you should in any subject, but especially in this case.
Now that that's out of the way, I just wanted to say that regardless of whether or not Jax actually comes out as transfem before the end of the show, I will still continue to write/draw her as such in my own fanworks. Big reason being that I genuinely believe that that's what the subtext given in the show is alluding to. Out of all the absolutely bonkers theories that the fanbase has cooked up, Jax being a closeted trans woman egg who desperately clings to the "role" of a hypersavvy masculine edgelord to protect herself from the horrors of the world she's trapped in and the dangers it and its inhabitants might inflict upon her (perceived or otherwise) for allowing herself to be open and vulnerable, despite the fact that the people in question would be more than happy to help her with her self-actualization journey, if her pride only allowed her the chance to reach out to them-- [deep breath] well, it's just the one that makes the most sense to me, and I think it would really help bring Jax's whole character arc home. And yeah, could they have him go through a fulfilling, self-actualization arc about being vulnerable and not hanging onto grief at the expense of potential future relationships without him being transfem? Sure, in theory. But man, could you imagine a complicated, nuanced character with that kind of depth being a trans woman that we get to see come out in real time? That'd seriously be awesome!
I've heard from quite a few real-life trans women and fems online who deeply relate to Jax's struggles with his relationship to gender, and seeing them all talk about it and what it would mean for them to see this theory be canonized is part of the reason I wound up getting so into it myself! Realistically, I'm not sure exactly where or how they'd manage to fit that into what I presume to be an hour and a half left of runtime for the show without overshadowing the other character arcs we've still yet to see realized, but I'm hoping for at least some sort of epilogue where she's out, transitioning, and ultimately feeling a bit better about herself. Bare minimum, I hope that Goose'll at least pull a Rob Renzetti and be like "Yeah I didn't intend for Jax to be transfem but the subtext is there so I'm happy to see trans women and fems seeing themselves in that character!" or even for her to say flat out that she did intend for Jax to be read as transfem and just didn't have room in the script to dedicate to her coming out arc. But either way, the show's not over yet, so I remain hopeful that we'll get something concrete!
That said, if it winds up not being canon, I can't blame trans women and fems in the fandom for feeling a let down by that, especially when there's so much in the text to back it up. We really don't get enough solid transfem representation in fiction, and that's just the truth of it. And when it comes to general queer rep, I don't think a character needs to be a shining champion of goodness and moral purity in order to be "good" rep, they just need to be human. Jax is undeniably flawed as a person; but if you look past the edgelord facade, it's easy to see that they are simply a hurt and scared human being who wants to love deeply and sincerely, but is held back by anticipatory grief and a fear of being perceived as weak for letting others see that softer side of them. And we've seen in small doses that Jax has the capacity for kindness and humanity, he just desperately needs to get over himself and allow himself the ability to show it.
And I do think that her coming out could accomplish that, especially if her transition ran parallel to her overall healing journey: needing to be truthful about her feelings, fears, and desires with the others, seeking their help, making amends with the ones she's hurt in the past by admitting how much of the harm she caused was from unresolved insecurities and envy. There's some great potential there!
So yeah, suffice to say, even if it only exists in my own "delusional" headcanons, I will continue to draw, write, and interpret Jax as transfem. That's what makes sense to me, so that's what I'm going with.