That's not a bad idea of a defensive posture or limited area for fighting.
However, if small dispersed ships were the way to go why is China, Japan, UK, France, US etc... all building larger ships with more capability in them. They are all introducing new carriers or carrier programs into their fleets as well. They are building bigger better submarines.
Because these vessels do the job and project the power. Small dispersed ships are a nice idea but don't pull the weight when the chips are down. There are massive disadvantages to them. They are not good in the high seas, they have limited sensor capabilities, they have limited ranges and time on station. This is why you see small ships in places like the Baltic (Sweeden and their Visby class) or the Black Sea ( the ever-growing number of over gunned Russian Corvettes and missile boats).
It's also why the LCS program failed at its heart and is being replaced with frigates. It was designed with the idea that quantity has its own quality. Well apparently quality is important as well, and the LCS actually showed that they were less flexible than blue water destroyers in most circumstances.
USV's can mitigate some of these disadvantages but in the process create their own sets of negatives. Complete lack of flexibility, limited sensors, no kinetic effects etc...
I'll take it as read that you need good sized hulls for an expeditionary force. But the PLA(N) seems to me to be only starting to find its way out to blue water.
By my count (based on wiki) the PLA(N) comprises
some 241 launch platforms for the 230 km C-801, 803, YJ-83 series SSMs - these consist of
123 missile boats in the 170 to 520 ton range (Orca displacement)
72 corvettes in the 1500 ton range (Kingston displacement)
46 frigates in the 2000 to 4200 ton range (the largest being comparable in size to the Halifax)
some 36 MCMVs in the 400 to 1200 ton range
some 62 light amphibious transports suitable for crossing the Straits of Taiwan - consisting of
33 in the 800 to 2000 ton range (Kingston)
49 in the 4170 to 4800 ton range (Halifax)
I would suggest that that equals some 339 surface targets for the Taiwanese to manage.
On the Blue Water end of things
42 Destroyers in the 4800 to 7200 ton range (similar in displacement to the Type 26 - Ivar Huitfeldt generation)
8 Cruisers in the 13,000 ton range (larger than the 9600 ton Ticonderogas)
8 LPDs in the 25,000 ton range (San Diego - Bay Class)
3 LPHs in the 40,000 ton range (America LHA)
2 CVs in the 60,000 ton range (QE II Class)
They also have some 40 subs of which 7 are boomers, 12 are nuclear attack subs and 22 are conventional.
I believe that the PLA(N) can keep the USN away from Beijing. The US can't invade.
I believe that the light amphibious fleet was no threat to Taiwan. It is problematic for the Phillipines and Vietnam et al.
I believe that the Blue Water fleet presents a current threat to Taiwan - but it still only adds 63 targets to the previous 339 bringing the total up to about 400.
I believe that the Blue Water fleet gives China the opportunity to fly the flag anywhere on the high seas. Exactly the same way the Brits are currently.
I don't believe that that fleet can, in any way, challenge the US Navy for dominance.
It can frustrate the USN and US diplomacy. It can't defeat the USN.
So the question becomes, in my mind, how important is it to challenge China on the 9 Dash. Is the effort to defeat or frustrate China? Or is the primary focus to prevent the locals losing their ability to act independently of China?
Now what type of fleet is needed?
Edit - Taiwan is 400 km long and the Taiwan Straits are 180 km wide.