My thoughts go the other way based on reading and interviews watched on American telly.
China may benefit from a weak Russia depleted by Ukraine, thats China The state. Publicly to not annoy its larger customer base it will do things like turning away misappropriated aircraft as you mentioned. However, Deng Xiaoping has a relationship with Putin which will cause him massive loss of face if Putin fails. Given we never know what these blokes talk about but there was clear assumption made early on that Deng asked his mate Vlad not to invade until after the olympics. Post invasion I recall seeing on this thread vids made by Chinese news crews embedded with the Russians clearly putting a positive spin on Russian success. If Deng looses face on an international scale his successor will rapidly move to fill his shoes.
Just my opinion based on bits and pieces of reading. China the state cannot allow itself to be compromised. Deng the leader cannot afford to be embarassed by his choice of mates - “yes Vlad I agree, NATO is a mess, Ukraine will be yours within a week, and when they are all still reeling from that I will roll into Taiwan. We can rule the world together”.
The U.S. says Russia has asked China to provide military equipment to assist with its war in Ukraine and that China has responded affirmatively
abcnews.go.com
The United States told allies in NATO and several Asian countries on Monday that China had signaled willingness to provide military and economic aid to Russia, at Moscow's request, to support its war in Ukraine, a U.S. official said as top U.S. and Chinese officials met in Rome.
www.reuters.com
The Chinese military is sending a delegation of troops and military vehicles to participate in a series of military competitions in Russia next month. On
americanmilitarynews.com