If Russia decides to start an armed conflict with Europe/"The West", then this is what will most likely happen.
Xi and his cabinet are only interested in widening "the central kingdom", and unlike Putin, Xi is no fool.
If it happens, Russia is facing economies it cannot oppose and it will lose. At that point, Xi will help Europe in some way, and as Russia loses - and loses hard - certain Eurasian oblasts and republics will be absorbed into China...
..which is good for those republics and oblasts, because Russia dgaf about them. Their only reason to exist is to give Moscow taxes, with no services or infrastructure levied can, something that will also help to motivate these oblasts and republics from Russia.