Let me ask you to consider this, OP
I'll assume, for the sake of argument, that you are male or AMAB, as you might say.
Imagine a man - many men in fact, in powerful positions and with a strong public platform and funding. And those men follow you wherever you seek refuge, no matter how hard you try to separate yourself. And they insist that you are the same as them. And to illustrate their point, they point out your bodily similarities to them, and then they list off a roll call of ridiculous macho attributes which they insist that they and you both possess, on account of you both having the same anatomy, since, by their logic, male anatomy always pairs innately with macho personality attributes.
And whilst you can acknowledge that you have similar anatomy, you refute that you share these macho attributes with them. They may be paired with the other men, but they definitely aren't with you, yes? And that absent pairing has great significance to you.
I'll assume that at this point in this hypothetical scenario you want to escape with all your might from these men who are associating you against your will with attributes you know you don't possess. They are telling you what you are, and you don't like it, and aside from your body, none of it is true. You want to distinguish yourself with great vehemence.
This is how I feel.
When a man calls himself a transwoman, and calls me a ciswoman, and tells us we are both the same, that he has observed what I am as a woman and determined my 'woman' characteristics and concluded I am the same as him. So I must not be allowed to separate myself from him.
But all your perceived 'woman' attributes are wrong. I don't have them; they aren't paired with my anatomy, nor any woman's.
And you don't even share my anatomy, nor my experiences that are pursuant to it.
We are not the same, and I will not be designated by you.
Don't be surprised by the anger you see from some women at the prospect of some men redefining women to match themselves.
Just think of the depth of feeling with which you want to distinguish yourself from men; who DO share your anatomy.
And then multiply it by 100 for me, a woman, wanting to distinguish myself from transwomen, throwing in the factor of our not even sharing anatomy in common.
You cannot force non-consenting people into a category with you based on a lie of attributes they don't possess.