Don't underestimate how much of the US's problem (and UK, Canada, etc) was caused by obesity, too.
https://www.sciencemag.org/news/2020/09/why-covid-19-more-de...
https://www.sciencemag.org/news/2020/09/why-covid-19-more-de...
Average age in the US is 38.
This probably accounts for the difference in death rate.
> We didn’t understand early on what a major risk factor obesity was. … It’s not until more recently that we’ve realized the devastating impact of obesity, particularly in younger people,” says Anne Dixon, a physician-scientist who studies obesity and lung disease at the University of Vermont. That “may be one reason for the devastating impact of COVID-19 in the United States, where 40% of adults are obese.”