I find the Khelif debacle incredibly damning for anti-trans militants since she apparently was born as a woman and has this weird thing where she has male characteristics. The anti-trans hysteria at that point in time was super off-putting for me since she did nothing wrong but merely existed. Before this I was like... meh, have sex separated sports and be done with it, but this made me re-evaluate my views in sex in that it's much more fluid than I gave it credit for. And this, by "nature", without human intervention.

I don't see anyone ever going "oh, Michael Phelps has unfair advantages because of this crazy gene". Then, it's fair and square, just better genes life's not fair. No, suddenly the care now, eeeeveryone cares now about woman's sports because someone with a rare genetic disorder showed up in the spot light. Utterly bizzare for me.

You need to read up about XY 5-ARD (the condition Caster Semenya has and Khelif surely has). Being XY with active SRY means you're male. Khelif has admitted having the SRY gene (in an interview with L'Equipe). Males have very significant advantages (50% plus) in power sports such as weightlifting and, yes, boxing.

Sex isn't "more fluid". It's entirely binary, but DSDs (differences of sexual development) can make appearances deceptive - so an XY male can be wrongly recorded as female at birth, especially in countries with inexperienced medics and midwives.

Phelps's records have all been broken. By other males, of course - no female is getting close to his numbers. That's male advantage in action.

You have it backwards. Khelif is what changed everyone's mind and supported the ban on trans athletes. The fact this person who was visibly male and was failing genetic tests as a woman and then brutally beating up all the other women is exactly what transphobic activists had been preaching about. The fact this happened on the highest stage of sports basically forced the Olympics to change their mind.