Or alternatively Beijing can supercharge US-led efforts to isolate China in exchange for contributing to a strategically irrelevant campaign. Tough call.
How can China be "isolated", pray tell? Year after year China's trade goes up, its FDI (both inbound and outbound) goes up, and its trade surplus goes up. If Westerners think they can live without China, they should burn every single thing they own and live in caves, because that's where they'll all be without China.
Isolating China is impossible. It is impossible in the sense that repulsive gravitation is impossible - it's just not how the Universe works.
By the way, Russia's campaign is the most important strategic event of this century. Although I support China refraining from direct involvement, it's very much China's fight.