Key word: Incomplete. As was Drostens study about the virus concentration in children. The German Fox News wannabe BILD tried to kill him for it. Incomplete studies and data is the norm right now. I am happy to not have to make decissions about life and death based on this. Someone has, so. And erring on the side of caution isn't necessarily a bad thing.
The DGPI data is not a study, but rather they collect data from children's clinics and it is incomplete in the sense that not all clinics deliver information to them. If anything there could be more hospitalizations and deaths, but that seems rather unlikely.
In any case I agree that the topic COVID and children is particularly sensitive and still blurry right now.
So far it looks like these are the absolute exception, but it does sadly happen that young healthy people and kids too get seriously sick and sometimes even die.
The German pediatric association publishes some (incomplete) stats about the disease in children (https://dgpi.de/covid-19-survey-update-kw22/) and there were so far 159 hospitalizations, with 21 of those in intensive care. 140 kids were released, 1 died. ~9600 <19yos registered as sick with COVID.