Actually, China is in a very good position right now, a Kingmaker so to speak.
They can help Russia, who is actually a competitor, survive through trade, or they can see/seize an opportunity and let Russia implode, strengthening their position in the World market.
If I was Chinese, I'd let them fail & get the rebuilding contracts in Ukraine.
It's the smart thing to do
There is no downside to China.
Actually it would be great propaganda/PR
"We stood with the World"
Yea, they'll fuck Russia