Do you have a rabbit hole entry point for the downfall of the Mayan civilization, specifically the climate factors? It's a civilization and series of events I know little about but is fascinating.
https://www.annualreviews.org/doi/10.1146/annurev-earth-0601...
Basically political and economic dysfunction combined with drought and soil degradation over a couple centuries.
But it was the resulting warfare from all that that really fucked then up.
But post-classical Mayan civilization was still healthy and large in scale. Just not the same kind of thing.
It would be a mistake to say their civilization ended then. It simply changed.
The Spanish killed it though. Killed it so systematically it became myth for centuries