I would like to know whether the excess child mortality is something to actually worry about, let's say if I had kids. There is a chance of my kid being eaten by a leopard but here in the urban US, it's unlikely enough that it's not one of the hazards I take special precautions against. Again, it comes down to the likelihood, which means what is N. If you don't know N, then describing a related number as "staggering" is just a bluff. Let's presume "child" means age < 18, and my kid is currently 8. What is the likelihood of his not surviving childhood, compared to other countries? To find that, you need N, or something computed using N, such as life insurance premiums.
It's editorialization but less of a bluff to describe global warming as staggering, since it can be backed up with evidence of real impact that it has on everyone, where it is going, and that it needs interventions if it isn't too late for those.
By comparison, look at the freakouts about kids being abducted by strangers. It happens and it makes headlines, but it's very rare compared to abductions by relatives, for example. I'm very glad to have not been overprotected from this when I was a kid. Being able to go out by myself when I wanted made me independent in a good way, imho.
The child mortality difference sounds to me like a consequence of the well known suckage of the US healthcare system, but wrapped in "think of the children!"[0] breathlessness. If it's disproportionate I'd like to see data indicating this.
And yes, COVID affects children[1,2], another example of crazy US COVID policy.
[0] https://en.wikipedia.org/wiki/Think_of_the_children
[1] https://www.imperial.ac.uk/news/242894/covid-19-leading-cause-death-children-young/
[2] https://www.thegauntlet.news/p/long-covid-is-now-the-number-one