Doesn't your link say that it was transient and temporary?
"No definitive case of myocarditis was found. However, the two participants (both women) with vaccine-associated myocardialinjury and chest pain met the Brighton Collaboration case defini-tion Level 2, indicating probable myocarditis in those patients (0.3%[95% CI 0.1–0.9%])"
So 2 of the participants had a .3% possibility?
Every result reported in the paper follows that same pattern: "[N] participants had [result] ([% of participants], [95% confidence interval])".
And note that your own link said that the .3% of participants were those that could possibly show signs of myocarditis, they didn't actually contract that disease. So what does your paper show that is damning evidence to you?