The general is a fool.
Even if China could seize Taiwan in a brilliant blitz campaign, which is doubtful, the USA and Japan would blockade their oil from the Persian Gulf through the Straits of Malacca, and their economy would soon collapse. And the official sanctions and private company actions would also devastate them. Xi Jinping is no fool, and he has figured it out. Even with a moron President like Biden, China is under control.
Russia produces oil and there is a land route.
China gets at least some oil from a Russian pipeline
Transneft.
China need only wait—the opposition party in Taiwan wants re-unifications. A few million in Bribes, some slick ads on TV—The Taiwan Government will join China by choice-—with promises of freedoms (like Hong Kong had).
The Chinese are being controlled even as they are massively building up their military, spreading around the world buying assets, and hollowing out America's industries. Your confidence is not reassuring.