[rossnordby]

I believe that is correct. I don't have a great source handy, but here's a preprint which agrees:

Conclusions: Myocarditis (or pericarditis or myopericarditis) from primary COVID19 infection occurred at a rate as high as 450 per million in young males. Young males infected with the virus are up 6 times more likely to develop myocarditis as those who have received the vaccine.

https://pubmed.ncbi.nlm.nih.gov/34341797/

Not sure about ratio age dependency. My prior would be that it is similar, since I don't have any reason to suspect otherwise. Still not a doctor or biologist though :P