If China makes a move in the Pacific, ain't nobody "stopping" them unless Japan has been secretly building Gundams or something. The USA can't even stop tribals from launching rockets at container ships in the Red Sea.
Discussion
China imports half it's food. The US will likely bomb the Taiwan Fab plants and then prevent food imports.
No one wants to go ten years without a new I7 gaming PC or new iPhone.
And China doesn't want half it's population to starve.
It's very unlikely but not impossible.
China's shrinking population means shrinking economic power so they could lose their chance to take it.