You probably misunderstood my point. Simply saying, tying Rouble with USD (Already did) and RMB would not help. In fact, if Rouble was tied to RMB, it would actually hurt RMB value.
Think of it like this. If you tie Rouble to RMB, where the exchange rate is more or less fixed. Problem is, Russian currency is depreciating like crazy, that mean in order to stop the depreciation, Rouble would need to print more money. Now, if China ties RMB to Rouble, and Rouble keep printing, basically that would mean Russian can literally buy RMB in the infinite. Basically, in layman term, it would mean the Russian is using their toilet paper to exchange for real money of RMB.
Hence I said, the only way China can help Russian is by buying some of their debt (Bond) but if Rouble keep depreciating, would China buy into their debt?
Trading resource is the same thing, bear in mind Russia only have Oil and Natural Gas as their natural resource, so literally whatever Russia buy from China. So, everything from Food to Clothing to Electronics. That's heck a lot of oil they will need to pump. Okay, even if Russia agree on Chinese Price, they can only pump oil to pay for whatever they need from China, and the law of supply and demand kicks in. If Russia keep pumping oil, then their oil would become worthless as they would flood the market and China cannot take on oil forever only needs oil as long as Chinese need them. At some point when the need and reserves have been filled China would not need oil from Russia Anymore. and if that happens, you are going back to square one.
You are right about one thing tho, no amount of sanction can destroy one's economy, but sanction can literally turn Russia into North Korea. The world is too big and the world can ignore Russia as a market, but Russia cannot stand to ignore the world and only trade with China, or Iran for that matter.