I agree that the ZGLD ETF is probably the "hardiest" of the bunch. But this ETF is not available for purchase by Americans. You could jump through some hoops to get it on a foreign exchange, but this is a bad idea because of potential tax and other issues not being registered here. So even if you can buy it, you should be aware that it is strongly discouraged.
What tax and other issues are there?
Who is "strongly discouraging" it other than you?
...Probably the best form of paper gold, with the least layers of intermediaries, is the Perth Mint Certificate or Mocatta Delivery Order as that is specific title to a specific claim of assets (if allocated). Very easy to transport across borders too......But, Hong Kong is the next best place for storing gold after Switzerland. They even sell gold in ATMs over there!...