Mortality rates are kind of useless to speculate over at this point. This is not a rate problem but a capacity problem. Even a novel flu with a mortality rate of .1% can strain the health care system. A coronavirus with no immunity and a mortality rate of 0.6-0.7% (true, infection based) is catastrophic. On top of that, once the medical system is adequately wrecked, the mortality rate shoots up. When ventilators no longer are available, more people die.
Right now on a daily basis, COVID is the 3rd largest killer. In the next few days on a daily basis, it will be the largest, surpassing heart disease in this country:
https://www.newsweek.com/coronavirus-no-3-cause-death-us-after-heart-disease-cancer-1495506
On top of all of this is the chemotherapy being delayed, the drug supply shortages, the less and less ICU capacity to handle strokes and heart attacks, etc.
Quibbling over death rates Being 0.7 or 3.4 in a pandemic is next to useless - when all is said and done we will be able to look back and calculate it properly.