Given the energy sanctions on Russia after they invaded Ukraine, China could reasonably expect similar sanctions on their imports should they invade Taiwan. They are just trying to survive. I don’t think they mind cleaner air, but I don’t think it’s their priority.
I get that you ascribe their renewable push to ulterior motives. But it began years before Russia did its thing, and while Xi was still the Belle of the Ball.
Ofc we don't need to imagine... we can just read the imperialistic propaganda being fed to the Chinese populace. Its very anti-american and movies about repelling american invasions (historical or fictional) are very popular.