I am not aware of any definitive evidence either way on whether lockdowns are good or bad for physical health.
They are clearly bad for people's mental health (except adolescents) and are horrible for the economy. However for physical health we have a variety of effects. Positive ones include reduced car accidents and communicable diseases of all kinds. Negative ones include more suicides and less preventive care. I don't know how they balance out.
I don't think anyone does yet, and there's still the massive confounder of 'covid'. But it's hard to say for sure that excess deaths above normal beyond what are reported to be from covid are missed cases, when we don't know the size of other effects.
It is hard to say for sure that ALL excess deaths above normal are COVID-19. But it is extremely likely that there are a lot of excess deaths that are. Even though we don't know the actual breakdown.
Unless lockdowns are rather bad for one's health, you mean.