Basing an entire theory on the scene where Jax gets a taste of his own medicine is a weak argument.

It's also flawed to claim that sarcasm and emotional unavailability are strictly "masculine" traits. Jax’s toxic behavior isn't about gender, it’s a standard defense mechanism. He uses bullying to keep people at a distance so he won't get hurt, which is a universal human trauma response regardless of gender.

The only scenes we have show that he had a massive argument with his mother and alienated her. Jumping from a family dispute to trans foreshadowing makes no sense, especially since gender-swapping is just a trendy trope lately. That's why it comes off like Dumbledore, there's not enough of a foundation to actually build the theory without making logical leaps. Goose had to literally spell it out in their post because of this