This video is how I am afraid the CCP (even post-Xi) will think and thus choose negotiation over invasion. But the great opportunity now is not merely to take back Russian-occupied territory that belongs to China, but to maximize Russian deaths (in particular young Russian deaths, thereby reducing reproductive potential) to the point where Russia cannot recover. Sure, China may lose people too, but China is currently far more able to take the loss than Russia is due to the initial population difference. This is why wars, despite being expensive (as the video accurately points out), made so much sense in ancient times. It is a chance to damage enemies demographically to a greater extent than is generally possible via negotiation.
To illustrate this, let's use an extreme example. Russia's total population is ~150 million. If in theory we could eliminate all 150 million Russians at the cost of also eliminating 150 million Chinese (ie. 1 to 1 trade), this would be a spectacular demographic victory because Russia would end up at 0 population whereas China (with its current population of ~1.4 billion) would still have 1.25 billion* remaining.
(* If China plays its cards well, it could even improve its gene pool qualitatively via this event!)
The problem begins when you look only at your own losses instead of comparing your losses to the enemy's losses. Then you (as the video recommends) tend to try to minimize your own losses and end up letting the enemy survive.