Honestly, you are just assessing some kind of best scenario development for the US like the folks at CSIS and other US think tanks where every single country in Asia-Pacific is not only going to just supply Taiwan (like Europe & US are doing in Ukraine) but attack China and try to invade it. It is simply unrealistic, especially if the US does not enter the war. However, the moment the latter happens, Americans won't be able to "choose the level of engagement" because losing there would mean a total collapse of the US hegemony not only in Asia but all over the world.