I am definitely not an expert. This is from [this book review](https://www.thepsmiths.com/p/review-aztecs-by-inga-clendinne...):

"This same zero-sum competition extended to the Mexica army, which as soon as battle was joined became not an army but a swirling melee of individual glory-seekers. The purpose of the Mexica warrior was not the victory of the group, but competition with his peers, and the way to win the competition was to secure captives for sacrifice to Huitzilopochtli. This singular fact drove almost everything about Mexica combat strategy, or the lack thereof. Great warriors wore towering feather headdresses to attract opponents so that they could be disabled and sacrificed. The Mexica had projectile weapons, but specifically designed them to be non-lethal and only employed them for demoralization. The Mexica wielded long, shallow obsidian blades and flint-studded clubs that were designed to incapacitate by cutting a hamstring or crushing a knee, rather than to kill. The only way to advance as a Mexica warrior was to sacrifice more captives than your peers,8 and the incentives of the system shaped everything else."

After some more reading, it seems indeed that this Inda Clendinnen book from 1991 may be lackluster on how the aztecs actually behaved on the field