Rumored 555 might be the domestic version of the FM3000N missile. The missile was shown in the last Zhuhai show as quad packing on the U-VLS, called HT-1E in export form.
I find it unlikely that CASIC, which is the main SOE provider for China's naval missiles, not all, but mostly, will have two completely different missiles in development. Rather they would pursue the one design that has the most promise, and offered a nerfed version for export. Note that 45km is just 5km short of the 50km rumored with Missile 555. CASIC is also responsible for the U-VLS, the YJ-18, the HHQ-9, and the HHQ-10 system. The missile is active radar guided.
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It might be a copy of 9M96E, S350/S400. Max speed would be less than 3 Mach.