Just a nit on the 1918 flu pandemic: both numbers (750,000 Americans and 675,000 in the U.S.) may be right. Remember, the reason it was so bad and traveled so far is that it was at the end of World War I when American soldiers were in Europe and traveling back home. An American who died in Europe would be an American but wouldn’t be in the U.S. In actuality, as hard as it is to count COVID deaths today, with modern medicine and modern technology, imagine what it was like then. That’s why the numbers are usually given as a rather wide range rather than as a single number.
Speaking of the number of deaths, some on the right claim the number is overstated, often based on the idea that it’s in somebody’s financial interests to claim non-COVID deaths as caused by COVID. People who study morbidity statistics say it’s understated, based on comparing the total number of deaths with prior years.