2. In recent years, it is the USA which has focused on expensive and very high-performance AESA radars due to incoming supersonic/hypersonic missiles. In comparison, Chinese destroyers do not face large numbers of supersonic/hypersonic missiles. So I suspect that contributes to the much lower cost of Chinese destroyers.
IMHO the steel price and protections measures adopted by US Government will impact in final price of the nexts DDGs. 3.800 million dolars for a pair of DDGs it is really high. For sure being lighter in the case of Type 052D/E helps (only 64 VLS cells), and probably contracting them in more quantity helps to contain final price.