the belief about having changed sex that is to be protected from challenge by others.
You are just making things up now.
This belief is actually what is protected in the claim to transgender status, and it's important for feminists to understand this. 'Trans' is not an immutable characteristic of human beings, it is not even the state of having had certain medical procedures done to one's body. It is a metaphysical claim to be the opposite sex, and it is this metaphysical claim that is protected by laws that protect transgender status, and which is protected by increasingly ubiquitous social taboos, particularly around language. This reasoning was on display by the judge in Maya's case:
I conclude from … the totality of the evidence, that [Forstater] is absolutist in her view of sex and it is a core component of her belief that she will refer to a person by the sex she considered appropriate even if it violates their dignity and/or creates an intimidating, hostile, degrading, humiliating or offensive environment.
He is explicitly prioritising the metaphysical claim of the (hypothetical) trans employee to have changed sex, and saying that by challenging this belief, Maya is violating the hypothetical trans employee's dignity. This is what I mean when I say that what is protected in laws around 'trans rights' is not the right of the person to fair and equal treatment as a person, but rather the reification by everyone else of their claim to have changed sex.
This is why talk of 'balancing rights' is ultimately futile - you can't balance women's sex-based rights with 'transgender rights' when the foundational claim of the latter is the 'right' to be treated as a sex which you are not.
Trans activists understand this, that's why they are so uncompromising in their refusal to acknowledge that sex is ever relevant to anything. Not sports, not prisons, not medicine. To an outsider, it might look like foolish overreach when they go to the mat for male sex offenders in women's prisons, or men in women's rugby. Not so. They understand their cause perfectly, which is that 'trans rights' depends on a metaphysical claim, and thus the primacy of this claim must be asserted in all circumstances for it to maintain its coherence. They know that any admission that sex might sometimes be more salient than gender identity is fatal to the metaphysics on which 'trans rights' wholly depends.
My central point in this thread is not to offer legal advice (!), but to remind everyone of the broader societal trend that I see in motion, and to illuminate the underlying logic that is driving it, which IMO is what we need to be tackling, rather than throwing ourselves one after another on the rocks of a powerful cultural movement that at this point in time feels overwhelming and unstoppable.