Considering your vast knowledge on history and creative way of imagining What-Ifs, I think I have an interesting question for you. The Aztec Empire, imagine that they had a better trade and militar relation to their neighbors, more akin the early Robert Baratheon’s solid war alliance than to the Mad King’s enemies-everywhere stuff. Did they had a chance to resist Spain? To be traded-with instead of conquered?

Well, the Aztecs didn’t do a half-bad job of resistance in really bad circumstances, as we see from La Noche Triste. which almost wiped out the Spanish. So yeah, if things go worse for the Spanish, the Aztecs could have avoided disaster and given themselves an opportunity to consolidate their position.

To me, the question mark is smallpox. Even if the Aztecs manage to see off Cortez, smallpox is going to be wildly destabilizing and create vulnerabilities for the next conquistador to exploit, so victory against Cortez might just delay rather than prevent conquest.