What is the safest and most efficient way of owning commodities during a war?

Yes, I read the Ray Dalio article. While I’m not panicking that the world is going to end next year, I am thinking about left tail event protection. If there happens to be a war in my lifetime(world war, civil war, or even both), I would obviously want to hold some gold. Problem is, most people don’t hold physical hold and hold gold through ETFs instead (BMO, ishare, state street and so on). If it’s gonna be Armageddon, and these institutions go down, does that also mean the ETFs also disappear? Is there another way of owning gold without actually holding the metal? I guess if this is the case then this could be a bull thesis on bitcoin.