Risk of myocarditis following mRNA COVID vaccination is around 133 times greater than the background risk in the population
“Myocarditis after vaccination, firm data” [Official JAMA report]
https://www.youtube.com/watch?v=Hb1Xm1uaedU&t
You are engaging in a red herring argument. In the vast majority of cases myocarditis “is brief, self limited, and of mild symptoms”. The baseline number of cardiac events in soccer players is not statistically significantly greater after the introduction of vaccinations.
Additionally, it is not unreasonable to understand that athletes have a high incidence of cardiac issues related to connective tissue disorders. But, this would require an actual understanding of pathology rather than a cutting and pasting of an article that is unrelated.