I’m afraid you need to stop solely reading activist sources on this as you have got it so wrong.
Sex isn’t ’assigned at birth’ for anyone, including that tiny number of people who may be diagnosed with a DSD. Contrary to activist lies, they still have a verifiable sex and in all cases in Western medicine can have their chromosomes tested and be medically diagnosed at birth in the even rarer cases of visual ambiguity of genitals.
Cases like Caster Semenya and Imane Khelif come about because of inadequate medical facilities and possibly a lack of education in their countries but there is actually no evidence either male athlete was even raised as a girl. They have a condition called xy 5 ARD which is a male condition that results in a micro penis. In their male centric societies it is possible that they were thought to be girls but childhood photos of Caster has him in make school uniform and Imane’s family have been very opaque over the matter. All of his socialisation appears to have been obviously make, physical contact with unrelated males (his coaches), no hijab in a very conservative part of his country and a very male swagger as he walks around, the women scuttling meekly behind.
Their medical condition would have become very obvious at puberty as they have obviously gone through a testosterone driven male virilisation.
Neither Caster or Imane are ‘trans’ but their cases have been jumped on by trans activists as somehow their logic says that even though they are not even claiming to have a gender identity, their conditions have been appropriated nonetheless.
The vast majority of people with DSDs are not visually detectable as most just affect fertility and in some cases bone health. Thr surveys you referenced are not of people with a verified medical condition, but just of people who ‘identify’ as ‘intersex’ which, given the shameless appropriation of the condition by the trans activists is not going to give any usable data. It just serves to benefit ‘trans’.
Here’s a useful explainer from the NHS
https://www.nhs.uk/conditions/differences-in-sex-development/