Plenty of clean water and filters (with nearby streams to replenish if necessary)

A 4x4 Truck and plenty of outdoor gear.

My in-laws were crazy into prepping for about a decade--they even bought the Julie Rowe white tents and filled their basement with enough gear, water, food, and other sundries to equip the whole neighborhood. They too often told me that our preparation wasn't enough.

I, like you, told them that if having enough to survive a couple of months in the event of a disaster wasn't enough, then I didn't want to live long enough to see that hellscape.

The older I get, the more The Road seems to be what that kind of apocalypse would look like rather than any sunnier view.