You've already done what you set out to do.
You could have asked politely, instead of framing it as a loaded question.
I am quite sure it was deliberate to derail.
It's a bit poor, because if you had decided to start a new thread - other people might have been able to join in and read arguments on your specific question.
Instead, this conversation is hidden away on a thread meant as a brainstorm, speculation, thinking out loud, of how we could speak to the "other side" when aggressive trans rights activists are silencing us and threatening us with actual violence on a daily basis.
I note you have not condemned the inflammatory rhetoric or actions, or taken the time to ask questions about why "we" are concerned.
But fine, let's talk here.
Your Gaul analogy does not hold, in my view, because geography doesn't really apply here, and even from a cheeky Wikipedia, the say:
By the 2nd century BC, the Romans described Gallia Transalpina as distinct from Gallia Cisalpina.
Places are still places, and distinct from each other. They're not the same, no matter what you call them, Paris, Texas is not the same as Paris, France. Additionally: a) there would still be clear boundaries for the greater region of sub-divisions of any territories (which there isn't for the concept of "woman" when it becomes a matter of self-definition and an internal claim of identity), b) the trans and cis areas were separated by the Alps (an actual physical boundary) - which means you're acknowleging that sex is the dividing line here, c) you would have to argue that trans and cis were the same place (which is what you're implicitly doing when you say that trans women the same as women) - when they clearly aren't, d) you would have to start from the premise that you had one region that then expanded, and you re-named it cis/trans, but pretended the whole territory had some kind of properties of the original place.
A better analogy would be to say we have human beings, but they are separated into two by the dividing line of reproductive sex. Humans have called these two groups various names, but they are Female and Male.