I agree with your point that with low death rates it's important to try to determine which subpopulations are at highest risk of both (a) succumbing to the virus should they become infected and (b) vaccine-related side effects.
With respect to myocarditis, though, note that it is rare, and those affected recover quickly [1], and there are some recommendations about potentially changing the injection site to be further from the heart to lower the incidence of this side effect [2].
With respect to myocarditis, though, note that it is rare, and those affected recover quickly [1], and there are some recommendations about potentially changing the injection site to be further from the heart to lower the incidence of this side effect [2].
1. https://newsroom.heart.org/news/young-people-recover-quickly...
2. https://www.scmp.com/news/hong-kong/health-environment/artic...