I think the largest moving etf associated with gold was Jnug with a 3 year return at around 54%. If you're okay with yoloing your entire portfolio into a volatile etf you could have put in the shipping etf Bwet and gotten a 97% return.
This is the part of your plan that makes zero sense....... Yes, market instability usually increases the price of physical gold. However people who believe in gold as a currency alternative typically buy actual gold, not an ETF. If the dollar crashes how are you going to turn your ETF into liquidity?
I'm not betting on gold as a currency alternative. It's a pure speculative play. Central banks are buying gold to underpin their own currencies, and speculators will pile in when things come unglued. The dollar "crash" will effectively be runaway inflation. It will not instantly go to zero. There will be a point in time where I will liquidate and briefly go to cash, and then immediately roll over into another asset. My thinking at this point is potentially oil, as it is in high demand when there is war, and from my perspective we're teeing up WWIII right now. I'll make my decision when the time draws near. My expectation is that the shit will hit the fan within a year though. We'll see.