War is entirely more uncertain for China, and potentially more destabilizing with more to lose, than it was for Russia.
It is in Taiwan's interest to be at least as tough a nut as Ukraine is, and I think they are trying.
Yes, since and during the communist takeover of China, all of its military might has generally been directed inwards at it's own people, but they are still a military force and are well organized.
I'd equate the current period of the PRC to the Soviet arms build up of the Cold War.
As far as the Soviet military went, the fallout of that buildup, and the actual condition of the Red Army, are known after the fact now.
Skirmishing against a near-peer like India is probably better preparation for a large scale war against a well-financed enemy with modern equipment, doctrine, and Western support than Russia’s wars against lesser former Soviet states and in support of Syria.
We didn’t find that out in Ukraine, we’ve known that from fairly widely circulated news, often from direct participants in the corruption (such as the people to whom essential gear was sold), consistently since at least the First Chechen War of the mid-1990s (where sales of fuel, weapons, and ammunition by Russian military personnel with custody over them to the enemy were a significant and recurring thing.)
What we have learned in Ukraine is a better idea of the extent of the effect of that longstanding problem on current Russian military capacity.
Now, it could be that China has a similar problem and has been better at keeping it under wraps than Russia has been for the past 30 or so years, but there is not much reason to suspect that.