Sigh.
Bodies exist. Our physical sex has physical and social consequences, especially for those of us who are female.
Women and girls, in the original female sense of the word, historically and in many places still today have been literally lesser citizens simply because of our sex. We have been property. We have been banned from education, from owning property, from voting or holding positions of power, from rights over ou own children. Our bodies have been sexualised and exploited for sex and for domestic labour.
And even though these things may not be legally enshrined in most (not all) countries any more, nevertheless their deep roots in our culture still affect how we are seen and how we are treated, and how we see ourselves and interact with others.
These things are facts.
Deciding that the words "man" or "woman" actually mean something mental not physical doesn't change any of the above.
All it does is take away the language and connections to our cultural history that we as women (in thd original female sense of the word) need to share and make sense of our common experiences of sexism, and destroys the rights, resources and protections that were intemded to mitigiate the challenges of be8ng female in a default-male world not be homestly arguing for their removal but by debasing the language in which they are written.
So it's great that you are starting to think about this. But please don't assume the women here just haven't thought about things deeply or are less aware than you.
If you had done a search you'd know that the supposed "gender difference" brain scans shown by some research are well known and do not show what some claim they do. Brains are plastic - their structures are changed by how they are used. So these differences seen in scans (which by the way don't show gender differences at all, they show sexuality differences, and once those are acclunted for the brains of trans people aren't any different to the rest if their actual sex) can just as easily be the results of thinking a certain way not the causes of it.
But again, even if the scans had shown what you thought they did, all that would means is that there are some mental commonalities between the sexes. It wouldn't undo physical sex or the consequences of it. It doesn't mean a person with a male body is "really" female, really "a woman", unless you also change what those words mean.
If you think there's a good argument to group humans by personality or character as well as or instead of sex then great! Make that case.
But make it from first principles.
Don't just appropriate the existing words for sex as if sex and its consequences are something we can just shrug off. As if how a man thinks makes his male body in the real world, somehow magically interchangeable with a female one so much so that women who do not know him will experience his eyes in a shared space as female eyes, his body as a female body, his hands touching her for intimate personal or medical care as female hands because he somehow has a "female" personality.
Women are more than a personality trait or a feeling in a man's mind. We are the female half of the human race is all our diversity and we have the moral right to be recognised as such.