Many, many moons ago, I had a double major in college. My first love (study wise) Spanish, and archeology. While I learned that studying archeology is, yes, fascinating, you cannot pay a mortgage, or any other bill. Before dropping the archeology major, I was able to participate in some Kalifornia, and then Central American archeology digs.
Of all the books I wanted, or was forced to read, two stand out, and I recommend them wholeheartedly.
The Hummingbird and the Hawk - by R. C. Padden.
It documents much of the Mexico, and especially the Aztecs before and during Cortez. When Cortez arrived, Moctezuma II ruled. There was a General behind the scenes named Tlacaellel. Tlacaellel had the ear of Moctezuma I and II. It is a very well written book, using original, ancient sources.
My other favorite is The Discovery & Conquest Of Mexico by Bernal Diaz Del Castillo. He was a soldier under Cortez, and survived it all. In his old age, he was blind and poor. He was sad that he had not much to pass on to his children and grandchildren. He decided to document his account of what he did and witnessed. Being blind, he dictated the entire book.
You can see it for free on Tubi TV.
Make sure you click the Captions on, because they speak Aztec.