USV - Unmanned Surface Vehicle. Having a crew onboard means it’s not unmanned?We do still need considerable size of personnel (or a skeleton crew, at the very least) onboard, - Not just for daily upkeep and man-in-the-loop duties - But most importantly, damage control.
At present (and for at least much of this decade), I don't think that large-sized USVs (that are in the high-hundreds of tons and above) are entirely capable of conducting damage control effectively without human supervision and intervention - Considering how complex and intricate damage control can actually get, whereby even a seemingly unnoticeable leak from just a few pipes could risk capsizing an entire ship if no action is executed in time to address it.
In the meantime - Sure, it is entirely possible for China to replicate Sa'ar 6 corvettes of the Israeli Navy (which has 32x Barak 8 SAMs, 40x C-Dome CIWS and 16x Gabriel V AShMs) for service with the PLAN. But, the Israeli Navy is facing a very different operational and threat environment than the PLAN.
Therefore, if we want to fit 054A/B-like weaponry loadout (plus other kinds of systems) on a 056-sized hull, significant compromises has to be made - And that's not just with the ship crew.
Or, conversely - Build that warship with a bigger dimension and a larger displacement.
Anyways, these things are meant to be disposables and mass produced. If they get damaged and not sunk, they can be towed back to port for repairs.