And China has moved an aircraft carrier close to some Japanese islands (which they appear to claim are theirs).

apnews.com - Japan china warship disputed islands

Last month they had a carrier in the Philippine Sea.

news.usni.org - Chinese aircraft carrier shandong deploys to philippine sea

As long as we maintain a significant presence, China would have a problem getting across the strait to Taiwan. They certainly could launch aircraft and missiles. But getting troop carriers across the strait would be a problem, unless we just weren't paying attention and left the area unguarded. Or if we elect the convict.

China has a lot of chip manufacturing, but I can't think of a single western company that has a fab there. In fact, last I knew China had banned chips from AMD and Intel in their PCs.

The Philippines doesn't have the money to build ships or infrastructure in any quantity. But they have slowly invited us back in (e.g. they are expanding the Subic naval base a bit to accommodate larger vessels). In a conflict, the Philippines will need a lot of help. Which would be in our best interests to provide, even if we didn't have a treaty.