The Taiwan question is more of an economic question than the military capability one. The US military, if only decides to actively participate in repelling any attack against the Taiwan, will make the expedition almost impossible for the Chinese. But it will have huge economic costs for the Americans and almost everyone, hence the possible hesitation.
China, for all its propaganda videos and widespread digital wumaos, knows very well that it cannot militarily counter the US and its allies. Its energy and trade routes can be choked within a matter of weeks (both the Malacca strait one, and the one thru Pakistan). Its just that the economic leverage is way too high and the appetire for war is too less.
The US has a more realistic assessment if China's potential. They fought the Chinese in the Korean war.