I really suspect that this below is a story that gets pushed hard.
"By the time you find out you're probably in the middle of your sporting career and it'll be a big and very unpleasant surprise. You probably got picked on as a teenager for being "manly". You're probably really proud of your success and hard work. You might be relatively famous in your hometown. All of a sudden everyone is talking about how you were actually a man all along, you're accused of cheating, you can't play your sport anymore, people online think you have a penis."
In Caster Semenya's life, Semenya has photos of swimming in male swimming trunks without a top with all Semenya's teenaged male friends. I believe that there are no photos of Khelif released except for photos from being about pre-school age.
The chances in this modern era of a person with a masculinising DSD not being assessed for lack of female puberty when male pubertal signs have started showing instead is going to be very very rare. If it happens how at all. The knowledge of 5ARD seems well known even in impoverished countries.
And remember, a person without the ability to process testosterone or one that might have streak testes that don't produce testosterone, are likely to be included in sports still. That will be where the further checks come in to assess for masculinisation.
And if a person who has testes but cannot process the testosterone they produce discovers they have testes, it will be very beneficial for them to know this so they can get checked. Because those testes might need removing / monitoring.
Either way, the compassionate way to deal with these discoveries is to test athletes as young as possible, well before they start to be well known.