I don't agree with the idea that "European diseases" killed off natives, as we've not observed such population declines to disease with any other populations. Further, we know for a fact that less fatal archaic strains of diseases in Europe were already prevalent among native American populations, providing them with ready resistance to European strains. But that comes with a caveat. We do observe these declines when any population is in the midst of dealing with famine. Reduce a persons nutrition, their immune system's ability to resist disease and infection declines. Do this to a large population and disease spreads and in a host with a weakened immune system, you develop more virulent strains. We know for a fact that when the Pilgrims arrived in North America, the natives where in the midst of famine. Global climate and weather was changing, not majorly, but enough that it seriously affected agriculture. One's health declines when malnourished is very similar to what we observe with those afflicted with GRIDS/HIV/AIDS and most cancers. By the way, keep an eye on those you know who submitted to the covid "vaccine". Interesting times ahead for them as the cancer rate is already rising.