It is completely normal for young, healthy athletes to die like this.
This is a benefit of being fit.
Soccer players have been dying of heart attacks while playing in droves for years.
12 died in 2010 of heart attacks while playing. The World soccer league even had commssions in 2009 and 2018 why so many soccer players died of heart attacks.
https://en.wikipedia.org/wiki/List_of_association_footballers_who_died_while_playing
Most of the players had undiagnosed congenital heart defects as most tend to come from poor countries and some of it is genetic with players from Serbia/Kosovo and those areas.