“The report says he died on the field...”
“he was pronounced dead shortly after he was taken to a hospital.”
It’s not clear exactly where and how fast he died. As usual the report said an autopsy (which we will probably never hear anything else about) will be done.
Saving a penalty kick can involve a strenuous dive to one side or the other, unless he outguessed the shooter and stayed in the middle. In that case he could have taken a hard shot to the chest. Either way, that or the strenuous dive could put strain on the heart, even though, as somebody commented, soccer goalies are not running very much during the game, compared to most of the other players.
The frequency of this has definitely gone up in the COVID era, among athletes, whether it’s the same for the general population. I suspect the rates are higher in general, but perhaps not quite such a large increase.