How is China playing this?
You get yours while I get mine.
Then, time to think about our own borders since....
See that green territory in the northeast and the Shakalin Islands?
China needs Russia till it fills its own ambitions near its own borders, but it also needs the EU and the US for its economy, EU and US dropping in purchasing power means fewer products sold, fewer workers back home, so if things go out of hand Xi will suddenly change his tone about this. Till now they wait and see, unlike others, they have time for it.
China could take all of Hong Kong and Vietnam under their nation, like fully, and nobody will do anything about it.
Hong Kong was returned to China by the UK in 1997, probably you're thinking about Taiwan.
As for Vietnam, it's probably the last thing China wants to invade in Asia, probably less than even Japan itself, attacking a fellow communist country, after all, that happened there is something no propaganda machine could wash clean.