My response to this:
Firstly, there is no technology today that can make a man's body (hormones, genitalia, physical body and breasts) indistinguishable from that of a born female. It may be possible to create a superficial resemblance but the internal experience of that body is not the same. There is no menstruation, the vagina doesn't produce its varying mucuses and scents which over her life the natal women comes to know as well as her own hands, there is no memory of the body changing at puberty or memory of/anticipation of the menopause. Instead there are other memories, of surgery, hormones and transition, and the routines of injections and dilation. Furthermore, the skeleton, muscles, lungs etc do not become female, meaning the athletic capabilities of this MTF body are different to those of a female body. The adjusted male is not experiencing life as a female person simply because his male body has been given a superficiality female appearance.
Why does this matter? Because the discussion about who "is" a woman is not simply a philosophical game. The claim of male womanhood is being leveraged to open up formerly female-only resources and protections to male people. So the question must also move from the philosophical to the practical. Why do these provisions exist, and does the adjusted male, by virtue of his physical adjustment towards a more female-presenting exterior, now have the same needs as female people?
I found it telling that you said "are all physically different" rather than "female". Whether conscious or not, this suggests to me you do understand that the adjusted male body is not a female body. Furthermore, it betrays a belief that womanhood is a function of difference to a male norm rather than a thing in itself. The adjusted male may be significantly changed from what he was. This does not mean he has become female.
In the case of sports or anything to do with female biology and medical care, clearly the difference matters. The adjusted male body is not a female body. It has advantages in sport - maybe not as much as an unadjusted male, but still advantages. In medical care, clearly the needs of a true female body with a female endocrine system, female internal organs and female reproductive role are not the same as a male patient, but also, we respect that some patients may want intimate or sensitive care from someone who shares their body type - who knows "how it feels", who understands and sympathises from a place of experience.
What about more social provisions? The physical spaces that exist for privacy and safety, and the opportunities and cultural spaces that exist to empower women against the heavy structural imbalance of historic patriarchy?
This brings me on to my second point. A woman is not simply her biology as it stands in front of you today. She is also the life lived to get there. The challenges and needs she has as a woman are not just the intersection of the body she has and the way she is treated by society because of it, but also the way she has learned to think of herself because of it, because of the images of girl- and womanhood she has been surrounded by since birth, the expectations she has felt, the social rewards and punishments that have shaped her behaviour, her self image, her mental toolbox. It's a process that started the day she was born, and something an adjusted male, no matter how well he may pass today, can never share.
Similarly, the adjusted male has absorbed cultural ideas about himself and about women that formed his own understanding of self and other, and even if he now consciously rejects them, they are still part of his story and part of what formed him.