How so? If Russia loses, it will be because Ukraine was supported by a US-led western world that hung tough, and stood strong against aggression. That will send an enormous signal to other countries in the Pacific in terms of resistance to China.
How does that make China stronger? I see it as the opposite.
It is obvious. If Russia loses, it will be because it is weak and has a lousy non-nuclear military. If Russia loses, what will happen to Putin? What will China do if their weak neighbor is in disarray?