As this item makes clear, the USA controls both the seas in terms of surface warfare, but even more tellingly, convincingly controls the subsurface. Thus the USA has all the effective options at sea.
As well all prospective targets, and that is simply South Korea, Vietnam and Taiwan possess land forces capable of grinding up any Chinese expeditionary force that actually crosses their borders while providing a massive support base for USA air power acting in support. Yet even if the USA stood out, these powers will maul a Chinese land force in the early going.
What we are hearing these days can be described as military wet dreams largely disconnected from military reality. The fact is even a Chinese army matching the capabilities of its immediate opponents would be in trouble for in all cases, the defense has a huge advantage.
We forget that D day was only possible because the German Army had already lost it main chances in Russia and was in retreat. The strategic reserve was gone. Imagine attempting such a landing on Taiwan against a freshly mobilizing and angry population.
China thinks it can defeat America in battle