Everything is a matter of perspective. You believe that the gods they believe(d) in are not real, but to them, it was. They were happy in their ways of life until the foreigners came in and forced their beliefs on them. Are/were they better off being forced to stop? No way to know. Soldiers in ancient times thought it was better to die in combat than escape to fight another day.
The destruction of the Aztec empire is usually attributed to Cortés, but really he had 500 men, some horses, and some guns/arquebuses. Not quite enough to besiege and overrun an island-fortress with 200,000 inhabitants.
No, his secret weapon was 100,000+ people from neighboring tribes, who were very tired of having the Aztecs raid them for sacrifices and enslavement. This is also why the violence witnessed during the conquering was so brutal that even the Spanish tried to rein them in (without much luck).
Source (alternative frontend w/ no ads): https://yewtu.be/watch?v=or6W4sXpl3c