Have not seen any of these "official sources" from the Chinese. As far as I'm aware GDC is either an Indian or American operated faux news site like the mushrooms that are everywhere on Facebook and Youtube (90% of which are actually Indian even if they pretend not to be and don't disclose their locations). S-400 in its current form may not be able to really be effective against HGVs, ICBM warheads, and VLO targets. Shock horror lol. When Beijing bought S-400, they would have known this from the beginning and tested the system. It provides certain air defence gaps HQ-9B doesn't and this includes long range. The S-400 basically covers ALL of Taiwan and on paper approaches 1.5x the range of the HQ-9B, at least the long range missile does. The fire control and radar units are very different to the Chinese approach since splitting from the S-300PMUs and adopting Patriot style search and fire control radars. Perhaps there were/are things worth investigating and adopting with regards to the S-400. Intercepting HGVs and F-22s were never realistic except for fanboy noise.
Patriot style means they have both the search and fire control radar on the same vehicle, if not the same panel. But that's not true of the HQ-9. Like the S-300, HQ-9 uses a separate search radar and fire control radar, such as Type 305A and HT-233. That gives better redundancy, and an added layer of risk to the attacker. For example, against SEAD, only the search radars are used to scan the sky, but the fire control radars are kept quiet. If the SEAD aircraft strikes at the search radars, they won't know where the fire control radars are until those radars are illuminating them and missiles are already on the way. Destroying the dedicated search radars will not shut down the fire control radars which may have a search and track option on their own.
Having the search radars separate means you are open to using different search radars, including metric wave radars that work on VHF/UHF.
In the case of the Chinese S-400s, I suspect the Russian fire control radars may also be able to link with the existing network of Chinese search radars, including those metric wave AESAs as well as the Type 305A and 305B used with the HQ-9 complex.
Having dislocated search radars means these search radars can serve not just S-400s, but older S-300s, HQ-9, HQ-22, HQ-12 and HQ-16 batteries.
HQ-16 radar system is unique for having a dual band radar system, so it may be able to do search and fire control both in the same panel, but it still works with a dedicated search radar.