> I give odds of seeing the end of humanity in my lifetime at around 50%.

This is not well-reasoned.

Climate change, even in its most hysterical worst case scenarios, could make large areas of the planet uninhabitable, and cause massive migrations, wars, and famines. But it won't kill everyone.

Forever chemicals, even if you believe they're responsible for reduced fertility, haven't sterilized humans. We're not in the Handmaid's Tale yet, and if we were, it's pretty clear there would be resulting cultural shifts to address fertility.

Nuclear annihilation is not possible with current arsenal levels. You would need millions of high yield detonations to accumulate lethal levels of radiation planet wide. Nobody has that many nukes. There's enough to make large areas uninhabitable, but it won't kill everyone. Nuclear winter could cause famines, but isolated groups can use existing technology for indoor farming.

There are some things that could kill us off entirely (asteroid), but none of the things you mentioned are going to do it.