Even if there were war between China and the US over Taiwan (which is highly unlikely), I doubt the US would actually invade China with ground forces. The point would be to defend Taiwan from invasion, not to conquer China. Thus the US and allies would only have to destroy China's navy and air force, making any invasion impossible. I'm sure there would be plenty of airstrikes against the Chinese mainland, but still no ground invasion.

Once that phase of the conflict ended, things would wind down to a sort of cold war, with both sides staring at each other across the water and conducting ongoing small-scale operations. China would not concede defeat, so there's no telling how long this might last. It would probably be sort of like the Korean war - no official end, but a de facto permanent ceasefire.

All this would be very bad for all parties involved, and for the global economy. As long as everyone recognizes this, war is a very unlikely possibility.