You are somehow convinced that these brain studies are definitive proof that gender identity & biological sex are untethered. However the studies you claim support your position are plagued by small sample sizes and methodlogical flaws, therefore making any sweeping conclusions about brain differences questionbale at best.

You mention that there are "measurable brain differences" between trans individuals and those whose gender aligns with their biological sex. But experts in the field (ie. look up the renowned Gina Rippon) have repeatdly pointed out that brain differences are influenced by an host of factors and cannot be reduced to simplistic explanations about gender identity​.

Therefore, there's nothing resembling a scientific consensus. Infact, brain structure often varies so much across individuals that drawing any concrete link between differences and gender identity is pure speculation​.

As for the idea that gender is somehow separate from biological sex—biological sex, as determined by chromsomes and reproductive function, remains scientific fact. The existence of rare conditions like intersex do not undermine the binary reality of sex, any more than rare genetic anomalies erase the exitence of dominant traits in biology.

The line between science & ideology in gender research is blurry at best, and it's a stretch to believe these studies are evidence of a definitive separation of gender and sex.