Contrary to the wish thinking fantasy road trip scenario outlined several times in this thread, China might be able to launch a bolt out of the blue missile attack on Taiwan, it may even launch a fairly severe surprise air raids over Taiwan for a few days. That’s it.
Whatever invasion force that can be thrown over the syrait without any warning in a world with cm resolution satellite images is one the scale of several battalions, 10-12 on the outside, at most.
If these do not cause Taiwan to capitulate, then I think there can be no scenario where china can wrap up the war before full intervention by everyone who will intervene.
There is no way to accumulate land forces large enough to have a chance in hell of defeating the land forces in Taiwan, plus the supplies needed to enable it to function more than a few days, at embarkation points, plus concentrate the shipping and supporting naval units to enable it to land amphbiously against opposition, plus gather the supporting echelons for large scale intensive air operation to air bases within range, plus make civil defense preparations to receive casualties, receive counter fire on coastal or even inland civilian targets, all within a few days or even a few weeks. If it was accomplished within a couple of month, it would already be an epic feat of exemplary staff work and logistic miracles unparalleled in military history.
No surprise can be expected if these preparation lasts more than a week or two.
It has been said amateurs talk tactics and strategy, and professionals talk logistics. That the logistic challenges and timelines of mounting the largest amphibious invasion since D-day could be so trivially dismissed speaks to the seriousness of the people opinionating.