As many people in this and other threads have pointed out, we don't have any prior measurements, so we are absolutely unable to conclude that Rodriguez didn't have myocarditis and constipation of the heart prior to contracting COVID.
Since this is basically an anecdote we cannot conclude anything on the population
>a professional athlete... is someone watched over by world class doctors and who constantly has his performance, health, and bio data measured.
You can't compare the likelihood of a heart issue going undiagnosed in a professional athlete versus a high school kid or an adult participating in an unorganized sport.