There is no age group in which COVID deaths exceed the total caused by flu and pneumonia. Looking only at the flu, COVID is significantly less deadly than the flu for children under the age of 14, and causes less than 3% of all deaths in persons under the age of 35.
That suggests that there’s something about the way those numbers are constructed, or that the flu lethality is off the charts this year, or...that Pneumonia is the symptom. That would require deeper digging, but in any case clearly can’t be taken the way you’ve presented.
The chart is notable for its opacity, I’ll grant you that.
Something else weird now that I look more closely at your prompting: it reports 121K “COVID’ deaths, 131K Pneumonia deaths, and 52K “pneumonia AND COVID” deaths. Which must make sense to the CDC, but needs further information to interpret for anyone else. Including, apparently, me.