The Fermi Paradox says we should have contacted alien life by now

The Great Filter says we haven't because a civilization's capacity for self-destruction increases to certainty over time

I thought for us it would be an exotic technology or scientific discovery that instantly destroys on a large scale

Nope. Far more depressing and mundane

We simply watched ourselves destroy our climate and lacked the will to do anything about it because someone was making money off it

https://www.theguardian.com/environment/ng-interactive/2024/may/08/hopeless-and-broken-why-the-worlds-top-climate-scientists-are-in-despair