Gold is too expensive to buy right now IMPO but if you're going to do it, do it right, buy physical, and bury it.
Learn how to seal PVC tubes to be 100% waterproof and use a posthole digger. Put the top end of the pipe no more than 4 feet below the surface in a area that has historically never flooded.
Even if you have to flee the country, you can always come back and retrieve that gold, 1, 3, or 10 years later. DO NOT rely on GPS or something stupid to use as a marker, and bury it ONLY in an area where you are 99.999% sure will never be developed. You should divide the whole by 5 and bury in 5 different spots. Knowing where to dig here is key. Away from homes, away from low-flying aircraft, and preferably in a forested area that provides cover but it unlikely to burn or be disrupted.