I'm afraid that China will not let Russia fail. If it does Beijing will be surrounded and its oil and gas access will be completely dependent on the West (U.S.) . This Xi Jinping can not allow in a world of depleting energy resources. The level of Chinese assistance will depend on how badly mauled the Kremlin gets in Ukraine but it will not be allowed to completely implode.

https://medium.com/politically-speaking/why-taiwans-fate-is-tied-to-ukraine-s-9f5c2f3b52be