Shallow water (200 ft) is a disaster for subs. The straits is no place for a sub, even ours. I doubt the Chinese would even put subs in the straits, better they circle around and come in from the east.
The purpose of the subs is not to attack Taiwan, but to attack our carriers in deep water. China is preparing to go to war with the USA. It is also why they are getting carriers. Carriers to Taiwan is foolish, land is an unsinkable carrier in that case. Carriers are for forward force projection. Like protection of an invasion fleet.
But since Clintoon fired most of the real Navy Officers and put in perfumed princes in high places, it seems there are no tacticians left.