Right. That is probably the achilles heel of the PLAN amphibious fleet. These types of relatively LO ASM are detected late, at close range, so medium/long range area defence are at best of marginal utility. It will come down largely to point defence of each ship or group of ships.
If most small formations of ships crossing (which would be amphibs and even civilian sea lifts) do not have CIWS or equivalent, then loss ratio would be very high over time. That would not be sustainable if you want to keep the land forces supplied and reinfoced.
It's really a quite easy fix; would cost some money to install self contained CIWS units on most amphibs, but is actually quite affordable considering the alternatives. If you have all medium sized amphibs having at least one 730/1130, and one H/PJ-17 for each samll (500 tonnes or less) amphib, then they would be a much tougher nut to crack.
In an expanded beach head scenario, they would be at the periphery anyways, able to guard the flanks, whereas civilian sea lifts would be near the center of the beach head, furthest from the perimeters on land. There would still be losses, but most of the LRASM can be intercepted by landing covoys of amphibs going to and fro the perimeter sides of the beach.
