My take is that ETF’s are purely to divert buyers away from real Gold. They were created to enable funds that were banned from Commodity trading, so could not buy Crimex, only shares or physical, which they have hugely succeeded in.
As for manipulation the scum don’t bother to be smart and hide it in complex option structures, they just outright sell or buy, no-one talks about it, or investigates it, or if they do no-one gives them the time of day.
By the way it looks like the overnight SM mkt has a 1 % downside limit, from the scum…watch how often it bounces off 1 % down…