Taiwan is a little island. It’s about the size of Maryland. The eastern 2/3 is mountains. The western 1/3 is plains and where the major cities and port are located, approximately 120 miles from China.
Taiwan’s ports are all within short range missile range of China. Not to mention all the semiconductor fabs.
Taiwan, Japan, the Phillipines, England can all be attacked from the mainland. But can they be captured and held when they are defended by a sea-power?