I am not sure how sustainable would that be. China would end up with a lot of volatile and relatively useless assets. China's trade surplus is 1% of global GDP. It is not something you can shuffle around easily, especially if it becomes a collection 80+ local currencies. China would exhanging real goods for useless abstractions of value. So China has to increase its imports for optimal economic performance in such a world.basically, you end up seeing your currency appreciate from the surpluses and have to abandon some of the lower end manufacturing. In China's case, China would normally run a huge tourism deficit, so some of the surplus money will go back to the other countries.
And then, you probably also have to do currency swap with the other countries so they can have more RMB. And then you end up holding a bunch of their currency, which you can use to buy assets in their country or exchange it for another currency or use it to buy more resources. I think in China's case, it will be like the Saudis and end up buying a lot of assets or just generally investing in many global south countries, so that they remain dependent on Chinese supply chain and such. You can also use that money to finance infrastructure projects in the other country.
AFAIK China's trade surplus is one of the worst utilized assets in the world even today. It is largely used for holding a lot of forex and treasury bonds in other countries, mainly the US. A significant chunk of it is used for borrowing even more assets of the same nature. Its return is usually negative against inflation and is vulnerable to sanctions. It is fairly apparent why the Chinese govt is working to decrease USD cycling from China back to the USA and is expanding relations with developing countries. Consumerist turn is also a part of this (in addition to pure GDP growth goals)