According to this link 287 out of 568.000 has died from Covid, though that is in the age group 0-17 years.

https://www.statista.com/statistics/1191568/reported-deaths-...

If you assume that lung damage is to an extent irreversible and accumulates over time (peobbat less true for pre-puberty children than adults), then you'd expect lung damage to be less immediately fatal in the young yet still have similar effect, just delayed.

That is not a valid assumption. There is no evidence that lung damage is common in children, or that it is irreversible.