We should also not forget that this would send an indirect signal to Asia-Pacific (maybe even Central Asian) countries on how China views such matters
For example, if China is seen to support a military attack against Ukraine, countries in ASEAN would surely be alarmed and start thinking "if China doesn't have a problem with that happening in Europe, who knows if China will do something here?"
On the other hand, by supporting Russia for its security demands but not supporting military option, the countries would feel like even on serious diplomatic issues, China doesn't support invasions. Surely such a thing would be a relief for countries which have an (irrational) fear of China.
That's why I am saying these things are extremely complex. You have to take into account hundreds of variables and side-effects when you take such monumental decisions. I don't envy the jobs of diplomats and decision makers. Sounds like a job which is mentally exhausting