This is like this funny idea people had in the early 2000s that China would continue to manufacture most US technology but they could never design their own competitive tech. Why would anyone think that?
Wrt invading Taiwan, I don't think there is any way China can get TSMC intact. If they do invade Taiwan (please God no), it would be a horrible bloodbath. Deaths in the hundreds of thousands and probably relentless bombing. Taiwan would likely destroy its own fabs to avoid them being taken. It would be sad and horrible.