China is a paper tiger, they have almost zero combat experience in any foreign soil for over 40 years, and their population is aging faster than Japan or Korea. Russia was assumed to be a super power in military might, how have they been faring in Ukraine? There was no natural barrier between Russia and Ukraine, it was a vast plain, and yet Russia failed to "overwhelm" Ukraine.
Russia hasn't been a superpower since the USSR collapsed. It could easily overwhelm Ukraine if it fully mobilized, but they are playing a balancing act with only volunteer forces in order to keep the economy sound and limit the war's impact on the public.
China is quickly becoming the world's superpower. The weapons they are developing are incredible. China will at some point flood into west Asia through Afghanistan to protect their oil supply