Gold, inflation-linked things like beaten down oil/commodity stocks, apartments in fundamentally different locations (preferably cheap), but also cash for deflation (or bonds, but bonds are really no longer a thing since covid put a final nail into the yields, imho). And it's all about % allocation. S&P500 is great if you use it right, besides most of us already have a large exposure to the "US stock the world beater superman" via engineer salaries.
Farmland would be perfect, but unless you're actually a farmer and know how to survive on your own this is simply not in your reach. I'm just a software guy, really like this profession, but doing software mostly precludes having the knowledge of a farmer.
Care to elaborate on what specifically you are investing in?
Seems like if you were wanting to survive "things going south" that would entail productive farm land and some sort of "back to the land" style prepper homesteading.