I was thinking about going all-in or substantially into gold last night with an ETF like GLD or IAU because of doom & gloom... then I checked the historic gold prices. Holy. Shit. You could buy a ton for pocket change up until like the early 2000s. And it's been correcting back down to that low value steadily since 2011-ish.
I graduated in 2008 so that's been my belief and my observations for the last 8 years.
I wouldn't touch any material ETFs unless you are in for a short term trade. If you hold gold, it doesn't really make anything compared to the stock market. With an ETF, it's even worse. Not only is it impossible to get dividends, you are paying a fee for holding the ETF.
If you invest in gold, just buy it.