I am not any kind of medical professional. But if I had to guess, it would be Marfan’s syndrome, which, iirc, is a genetic weakening of the artery walls. Other athletes in the past have died rather quickly and unexpectedly from it, eg, Hank Gathers, Flo Hyman.
Marfan’s syndrome is a genetic weakening of connective tissues in general. It can be readily detected in eye exams.
https://www.nei.nih.gov/about/news-and-events/news/new-research-marfan-syndrome-focuses-eyes
I think the difference with those two greats is that it happened so long ago and we’ve come so far in detection and treatment. These players are paid so much money nowadays that you can guarantee they are checked over time
and time again.