That's not how the Open category in most sports works, as you know. It's for anybody in effect. It's only the Women's category that is protected. Your born female anecdotal friend can identify as what they like and compete in the Open category, or in the Womens category.
So no more scholarships just aimed at black kids? No more Women in Stem awards? No more Barbellion Prize for disabled authors? These are aimed at encouraging participation from underrepresented groups. Nothing to do with special dispensations or the participants being 'lesser' as you put it. But you'd bin it all as long as it meant men could be in women's stuff...
Stop saying 'STEM'.
I have headed up STEM depts in colleges. STEM is nothing to do with women's rights, it's about some of us promoting opportunities for women.
Trans people and non-binary people were welcome and their identities respected. There were never any issues with trans people in STEM. STEM has no relevant connection with sport.
Women were always welcome in STEM depts before, but quite often they didn't sign up or dropped out early. Those who dropped out were offered exit interviews, but pretty often were just asking to join other courses where their friends were, rather than other reasons.
We needed to do something that gave encouragement to other groups (not just women), and we were largely successful.
My formal learner I mentioned was a learner in STEM centre that I managed.
It shows how weak your argument is when you keep dragging this up.