Spanish conquest was centuries after the collapse of lowland Mayan civilization.

The end of the Classic period? Sure. The 200 year drought did not help by reducing agricultural capacity and the political upheaval tanked any ability to adapt of much of the cities.

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

Hm, I don't see the similarity then. The Spanish were deliberate and malicious. Climate change is a consequence of our own actions, although the accounting needs work.

Not a direct comparison, more a comparable level of existential threat.