there won't be much we can do at that point if the biological sex class formerly known as women has suddenly disappeared from all our laws
Well there will. We're 52% of the population, it just requires enough of that biological sex class to wake up, experience the thundering locomotive heading down the track the result of not paying attention and being kind instead of engaging the brain, and start getting pissed off. When you drive a major section of your population over the edge you have a massive, massive problem; which is why many of us here have been saying for years, this will end nowhere with sunshine and rainbows for anyone.
Lots of 'sex positivity' which is largely about removing boundaries and social norms (see the anarchy links to the lobby), which primarily reframe things to benefit male people at the expense of silencing and devaluing female ones. Likewise surrogacy: the rights of female uterus bearers and children don't figure largely anywhere in this. You may notice a glaring lack of equality and reciprocal values being demonstrated in the narrative.
Incidentally those driving the 'there is no such thing as biology/ no sex class/ woman is a feeling not a reality' muddled narrative absolutely know what one is when they want a surrogate or an egg donor, and have no difficulty at all knowing who to listen to with great respect and value all feelings and wishes of, and who to tell their problems, feelings, voices and needs don't matter and shut up or [insert death/rape threat here] Likewise don't assign labels to (some) people they haven't chosen and don't reduce (some) people to their biological parts, but other people are now cervix havers and uterus bearers and resistance to obediently taking on the label is evidence of unacceptable behaviour and prejudice. [confusion]
None of it hangs together. The only consistent logic that links it at all is that everything always a shifting constellation that ensures female people are suppressed and subordinated to the wishes of male people and not allowed an independent voice.