Number of registered cases of myocarditits after vaccination is not very different from baseline, while covid infection increses risk of miocarditis 16 times.

I wouldn't be surprised if incresed risk of miocarditis after second dose is completely explained by changes in behavior of people who finally got vaccinated after many monthes of lockdowns.

They probably started going out more and exposing themselves to coronavirus which vaccine provides partial protection against.

Researchers don't even exclude from this research people who got full blown covid before their miocarditis.