Again where are the sixty million??? Those are numbers that are not typically thrown around about native population
Here’s a paper that makes a claim for 54 million.
https://uwpress.wisc.edu/books/0289.htm
Others make claims as low as 8 million, others say 100+ million.
I don’t see that the exact number is important; the original claim is that most were killed by diseases their immune systems had never seen.