I'm going to try again because clearly I haven't explained myself very well. But first I'm going to establish some things I share in common with others:
Gender identity is not innate.
Mermaids perpetuate harmful ideology
Gender is bad and a tool for patriarchal oppression
I am not trying to argue for existence of a soul, gendered or otherwise
Gender is primarily a collection of stereotypes
Gender is a social construct
I agree with much of what others have said on this thread
BUT
(And if I get this right one day I will peak trans Supermatch)
Gender identity expression (probably more accurate than just gender identity) is something that is well recognised by psychologists and social scientists and is widely studied
The theory (which I am convinced is FACT) that gender is a social construct is relatively recent and has not had time to fully reach the mainstream before trans narratives have started to dismantle it again. My little corner of lower middle class suburbia is still highly gendered in its thinking 'boys will be boys, girls naturally prefer pink, Tom boys are the exception to the rule, men are naturally better at STEM' etc etc. So many people I encounter do have a gender identity. I know a lot of gender ideologists come here and say they can't explain it... it just is... but actually I think the difficulty they have is that they can't explain it without using stereotypes of one kind or another, which of course none of us can. But we can explain it when we recognise it is about stereotypes after all.
An example of gender identity is where we think we have chosen x, y and z because we like it and that we like it at least partly because we are female. But in fact we think we like it because we're coerced into liking it by societal expectations. Internalized misogyny is an example of a gender identity expression.
I don't want to deny the reality of that. I want to meet people where they are. Gender has affected the way a lot of people think, repeatedly, and, as their brains are plastic, over time that has affected who they are (in their brains not their 'souls'). It is connected with our bodies because other people categorise us according to our bodies but it isn't such a great leap for people to copy the behaviour more commonly associated with the other sex instead of their own. That will have to do with the way our brains respond to social cues as much as anything and that can be innate. Being immune to gender influence can also be innate because, again, this has to do with the way we relate to people socially e.g. ASD.
For those of us who are neuro typical and have had a fairly conventional upbringing the much greater leap really is to free ourselves from gender through active thinking. But if we are rad fems can we also recognise that having freed ourselves (in our brains at least) in order to help free other people from patriarchal oppression it would be useful to meet them where they are and acknowledge their experience, explaining to them how their experience is symptomatic of patriarchal oppression, instead of mocking, deriding or denying it. I'm thinking particularly of girls obviously.