The number of deaths divided by the number of confirmed cases, which comes out as 1.83%. That means that yeah, there are probably a lot more people who have actually been infected but not tested.

But for my very simple calculation of deaths, I used 0.2% among healthy people under 50. Perhaps that is still a bit high, let's slash it in half and you "only" get 100 000 dead in that group.

Here are a couple of paragraphs that stood out for me in the WebMD article:

Petrilli said it's correct to say that certain patients are at higher risk than others, including the elderly, those with chronic medical conditions, and pregnant women. "But that doesn't mean that the patients who are not in those categories are at low risk. It just means that they are not at as high of a risk."

Although age-specific mortality rate for young people is relatively low, they still suffered many excess deaths this year. Faust, the emergency physician from Boston, and colleagues authored a medRxiv preprint study showing that COVID-19 was likely the leading cause of death in people between the ages of 25 and 44.