I am afraid to ask this question too broadly but I would be very happy to get answers that included conflicts not just in the Americas. For example, India had superior rockets to those of the British but China's weapons and ships were inferior for some reason, even with access to European arms, I think.
Anyway: Cortez famously defeated the Aztecs with a handful of men and horses. He had superior weapons, basically the Aztecs had stone-age weapons when the Spaniards had gunpowder weapons. (Of course, disease played a role too.) My main question is, how long was it before the natives acquired gunpowder weapons? Is it possible that very deliberate policy prevented Spanish traders from selling guns to the native Americans? Or could the Natives have been reluctant to use such weapons?
Or did the equivalent of Aztec scientists (would that have been priests?) make the manufacture of firearms a priority and succeed to some extent in making such weapons and gunpowder? My sense is, no: It seems like even 300 years later, whatever firearms Native Americans had were purchased from whites and natives never made (i guess i am wrong even if in limited amounts) gunpowder. Is that really possible that in centuries no Native American gunsmiths and chemists emerged?