Ukraine war dragging on for multiple years in a quagmire has benefits for China.
1. It distracts the West from fully concentrating on China.
2. It weakens Europe which weakens the overall US+Europe block when they eventually gang up on China.
3. It makes Russia depend on China for its prosperity thus strengthening the Russia-China relationship.
This is why China is in no hurry to take back Taiwan by force.
"Sun Tzu's The Art of War" is the most important military work in China more than 2,000 years ago.
On the surface, he taught the Chinese how to win big battles, how to win more with less, and how to defeat the strong with the weak.
But if you study deeply, you will find out. Its content is not about the method of war, but the method of avoiding war; not the method of how to win the war, but the method of not losing; not the way of winning more with less, but the way of winning less with more.
For China, it's like a jungle adventure. If you have enough food and self-defense weapons and the road is in the right direction, then just keep going and wait for the opponents to go the wrong way and fall into a cliff, trap, swamp and be seriously injured or die; or have to ask for help after consuming too much food and equipment ; then you win. In the process, you don't need to kill the opponent, or even cause unnecessary trouble for the opponent.
Of course, people who are used to living in the "garden" will not understand.