Haven't RTFT.
I don't believe that I am defined by my sex. I do, however, believe that what makes me specifically a woman IS defined by my sex, because I believe that sex is the only actual difference between men and women. Everything else is just stereotypes, which I reject. This is why I don't believe trans women are women, or trans men are men, however nice they might be or however much they might genuinely believe in their identity.
Someone's personal identity is just that: personal. It doesn't define them in relation to other people. So take someone like Lia Thomas, for example, who believes that their own personal identity as a woman should entitle them to compete in women's swimming events, I think that is just wrong. Lia's identity has nothing to do with the female swimmers. They have nothing in common.
"Man" and "woman" aren't words we use to describe personal identities, they are words we use to distinguish between one half of the population and the other half, on the basis of shared characteristics. Women don't have any shared characteristics with trans women, and men don't have any shared characteristics with trans men. Trans women have a shared characteristic with men: being biologically male. And trans men have a shared characteristic with women: being biologically female. Nobody is "non binary"; that is a complete nonsense which relies on the assumption that everyone else conforms to narrow gender stereotypes associated with men or women, which we don't.
I think if you want the rest of society to treat you as being the opposite sex to the one you actually are on the basis of your personal identity, then yes, actually, you should have to do the emotional labour of being able to explain what the hell it is you are actually identifying with and what you think it has to do with other people.
Like you, I used to come at this from a "be kind" perspective. But now I see that the whole thing is incredibly unkind and unfair to women, and very damaging to children and young people. It absolutely does just reinforce regressive stereotypes. And for what? Who is benefiting?
Transgender males who say they identify as women get access to women's single sex spaces and women's sports, to the detriment of women. Transgender females who say they identify as men get...well, I'm not sure what, exactly. Nobody really cares which toilets they use or which sporting categories they want to compete in, because they're no threat to men.
But let's just look at the difference in treatment of transgender male athletes and transgender female athletes. Transgender male athletes are allowed to compete as women provided they get their testosterone down to a certain level, which is still much higher than any biological woman's level, and doesn't negate the advantages of having gone through male puberty. They get to compete as women even though they have a clear unfair advantage. Transgender female athletes, on the other hand, aren't allowed to compete at all if they have been taking testosterone, because it is a performance enhancing substance and therefore banned. It makes sense for them to be banned from competing against women if they have been taking testosterone, but there's no real reason why they should be banned from competing against men, since taking testosterone doesn't give them an unfair advantage compared to biological men. So transgender male athletes get to have their cake and eat it, whereas transgender female athletes have to choose between hormones and sport.
Take any aspect of this debate and ask yourself who has the privilege. It's always the ones who were born with a penis. Always.