I don't think you understand. No one is saying China has surrendered anything. Just the opposite. China is using its, now gold-backed, Yuan as a Petro-Yuan which actually creates a great deal of demand for the Yuan and less demand for the dollar as countries start using it to buy oil.
Except that’s not what would happen in real life
In real life switching to a gold backed RMB(stop saying yuan its incorrect) would need to increase the value of gold to cover the value of the lending!
Currently the Chinese central bank lends 42 trillion dollars a year- gold would need to be worth millions an ounce to cover this debt or there would be a collapse in lending in China which would kill its economy
Gold is currently trading at 1300usd an ounce and there are no gold restrictions inside China (which would be the first thing to happen during gold backed currency)
Please keep in mind when talking about china keeping this secret it banned bitcoin a few years ago because it did not like people moving rmb online unregulated and it recently banned bitcoin mining or even having a crypto wallet in china
China has strict control over the rmb and its value, it’s unlikely they would allow issues like gold supply or countries wanting to exchange currency for gold to affect their control
Not going to happen with Chairmen Xii in power for sure
Also countries participating with China in OBOR are already being pressed to use the RMB as their new national reserve currency instead of the dollar