Trans women are "women" only because you changed the meaning of a word. It didn't change reality one iota.
In reality, trans women have nothing more in common with female bodied people when they are called "women" than they did when they were called men.
So the only meaningful questions here are:
.1. Regardless of which group of peple the word "women" currently points to, do female people have a history of marginalisation that was specific to their sex and even today have significant experiences, need, risks or challenges that are different to male people?
.2. Do they therefore have a moral right to differentiate themselves from male people, to speak of female-only experiences, to organise politically to promote female-only protections and rights, and to organise socially for female-only spaces and opportunities?
As a feminist, I believe the answer to both questions is yes.
So regardless of what one believes the word "woman" to mean, I cannot see any moral justification for this social and political project to prevent female people from speaking and organising in our own right.
Either trans women are women, in which case being female bodied is something else, and that means trans women's needs, rights and experiences as "women" are totally irrelevant to being female and have no business being included in the consideration of what female people may need at all,
Or trans women are not women, in which case they have no business being included in women's spaces, rights and protections, or to take women's resources and women's language.
Either way there is no honest argument whatsoever that can ever lead to the conclusion that trans women have a moral right to appropriate the language, rights and protections of the female bodied half of humanity, because whatever it is they may in reality be, it is never going to be the same thing as natally female bodied.
And if you stopped only worrying about whether is fair to cause possible distress to trans women and also considered whether it is fair to take from female people, you would see this as well.