What Russia is doing in principle is detrimental to China. They've thrown aside the respect for the sanctity of other nation's integrity and sovereignty by annexing Crimea and recognizing the two rebel republics in the east of the Ukraine. By not overtly reprimanding Russia for its transgressive behavior China is demonstrating to the world that its
are self-centered: as long as you respect our integrity and sovereignty, we don't really care what you do with third party nation's integrity and sovereignty.
China needs to deftly balance support for Russian imperialism against US imperialism while at the same time appearing as the mature "Adult" in the room so the smaller powers in Africa, South America, Middle East, South East Asia view China as fair, objective, and impartial. Otherwise, calls for UNSC reforms will be reinvigorated to include more neutral India, Brazil, and South Africa who are all more assertively condemn Russian actions, particularly among smaller powers watching great power politics play out.
China can reasonably continue positive neutrality stance as long as the war is swift with concurrent ceasefire talks, and minimally civilian casualties,.
China's positive neutrality will turn to more assertive pressure for Russia to resolve things peacefully or pull back once the war enters long-term occupation with insurgency and mounting civilian casualties, Russia doesn't necessarily need to listen to China's advice. It's to put up a show.