One issue that has yet to be discussed is that US Naval operations are highly dependent upon data and communications using space assets, i.e. satellites, and observers of space warfare capabilities will note that China is on the forefront of spacewar capability; perhaps not quite on par with the United States, but conceivably capable enough of taking out many tactical surveillance satellites that are used to observe maritime operations in real time, as well as interfering with communications and potentially even denial of crucial azimuths in Low Earth Orbit. A conflict in which the US Navy no longer has eyes in the sky and reliable satellite communications, going into a constrained area where China has land-based air power and anti-ship missiles is not favorable even for a theoretically superior naval force, much less one that is going to have difficulty fielding and coordinating at full fleet strength. It would certainly result in holding US carrier groups back far enough to be out of range of Chinese anti-ship missiles, which means limited air coverage, ergo, the USN can do little to aid Taiwan directly against an invasion fleet and would struggle to bust a blockade.
The East China Sea is also relatively shallow (most of it north and west of Taiwan and the Chinese mainland is less than 200 meters depth) and has a variable thermocline which may not allow US submarines to use the tactics employed in the North Atlantic and Pacific Oceans with moving below the layer to mask radiated noise, which would limit operational speed. This area isn’t well-mapped by USN charts, while I suspect the PLAN has been working on producing detailed seafloor surveys; as a consequence, even with all of COMSUBRON Eleven added to the squadrons based out of Guam and Pearl, the USN submarine fleet would be outnumbered and operating in ‘away’ waters that PLAN subs and anti-submarine surface ships are far more familiar with. It is an unenviable situation even if you assume that the US Navy can field in full force with well-trained and led crew, and the even if you think that the Chinese are not at the same level of ostensible performance.
Stranger