First of all, if you do that, you still need to digest that "6 Trillions" Yuan you printed, and if it is like you said you are printing it every year, that mean you deflate your own currency by the same volume every year. Just because they are going to reinvest it back to China does not mean anything, the more currency floating in the free market the more it deflate your currency value. That's macroeconomic 101....6 times the currency inflation is a LOT in case you are wondering, and 1 trillions dollar added to circulation every year is also a lot. US as a whole, with massive Financial backing, only needed 2 trillions dollars in circulation, and you are talking about adding an entire US circulation in China every 2 years......
Secondly, you can't simply pick up all the Russian oil and gas. 1.) you had contract with other oil production country (Saudi Arabia, Qatar and Iran) So what is going to happen to all that contract? You get them as well or you just break them? Gas also is a problem, 2.) China don't use Natural Gas or LNG (not LPG) as much as the entire EU combine (China import around 50 billions cubic meters, EU as a whole imported around 420 billions cubic meters)
en.wikipedia.org
So are you telling me China is just going to stomach it (Bear in mind you can't sell them) or you are saying China are to ditch all their renewable and switch to gas as a whole??
Finally, infrastructure is different. Russian oil is not the same as oil from Saudi or Qatar or even Iran, Russian oil is heavy oil, Saudi oil is Light Crude, you can technically refine Heavy into Light Crude, but are you saying you are going to build a few refinery just for this change? Because you can just use them Russian Crude like you do with Saudi and Iran Crude. Another issue is all the delivery network Russian currently have is toward EU, you will also need to expand the network to even accommodate slight increase. Are you going to pay for that as well??