The problem with comparing it to the flu is that humans have some built in immunity to the flu and a vaccine that helps prevent infections. So, only 25-50 million people a year get the flu and .1% die for somewhere around 25-60k deaths a year. And the age is even more skewed to the elderly as well as no long lasting effects.
With Covid, we have no immunity and no vaccine to help prevent infections. So, let's say a really safe estimate is half of 330 million people get it before herd immunity slows the spread some and the death rate is 0.5%. That's 575,000 deaths or almost 10 years of flu deaths at the high end of estimates. In addition, we are only beginning to understand the long term effects this has on the body.