The issue underlying all of this is our laws and what the impact will be if they are suddenly blind to sex.
If none of us had ever heard of the word trans, and such people didn't exist, how would we respond if:
One day men announced that it was time to remove every reference to the female sex written into law, and all rights pertaining to the female sex?
And to regain any semblance of protection going forward, people would need to claim membership of a new group, with undefined characteristics, that any person, male or female could join. Any sex discrimination women faced in the past would only be answerable to in law going forwards, by virtue of one being a voluntary member of this male+female group with undefined characteristics. Which renders sex discrimination redundant. You don't recognise sex, you can't respond to sexism.
Bin legal recognition of sex; gain potential membership of a murky unisex faith based group without characteristics. If you're prepared to take up membership. If not, you're in no-woman's-land. The law doesn't recognise your sex, and you have no belief-based-characteristic to replace it with. You've nothing, no recourse now.
If that isn't the most terrifying prospect for women's rights in a couple of centuries I don't know what is.
That is pretty much how I assess the current situation, and I can do this assessment without referencing trans.
The proposed changes to the law are about erasing any recognition of actual sex. Entirely.
Even as I write that out I can't believe that LAW makers aren't sounding alarms. Instead they are celebrating this.