I'm shocked that we constantly allow neocons and NATO s.t.r.o.n.k. chuckle-heads to frame the debates, like how they claim A-235/Nudol is simply just a anti-satellite system. Talk about "finally" developing HGV's is funny considering the Soviet's developed the Buran which is essentially a civilian version of a HGV, and that was back with antiquated 1980's electronics. It's a strong likelihood that Topol/Topol-M series uses HGV warheads aided by the miniaturization that came with the rise of digital electronics (the 1980's didn't have smartphones ), hence the reason why Almaz Antey has now stated that the S-500 can now "intercept intercontinental ballistic missiles with the possibility of changing trajectory mid-flight."
...The only way they can reliable state the S-500 could engage ICBM warheads that can change trajectory in mid-flight is if they already developed that technology and from that they developed practice targets mimicking the characteristics. As far as the use of scramjets, Almaz Antey has stated that the RS-26 will be abandoning the 'bus' system in favor of individual warheads with their own propulsion, and it isn't a mere coincidence that Zircon will be coming in to force approximately around the same time frame/window. It's no wonder VKS absolutely refused to let U.S. START officials see what the RS-26's warhead looked like.
Good point about the unmanned Buran being essentially an early HGV, and I would add while I've never seen any data on the dynamic performances, I'd expect that the BOR-4 & 5 test vehicles from the Buran program in the early-mid 80s likely exhibited many of the qualities required by a practical weaponised HGV. I would not be surprised if the Yu-71 development has leveraged the technological legacy from these older vehicles, particularly for thermal protection systems (the testing of which was the main purpose of the BOR vehicles).
BOR-4 graphic below. Although this vehicle had rocket-powered propulsion for initiating re-entry followed by a largely ballistic path until final landing approach (rather than a scramjet used for active flight to target) I'd assert that it can still be considered a rudimentary HGV.
1-Nasal thermal shield; 2-Electrical battery; 3-Tank for the fuel, NO3 + UDMH; 4-Parachute; 5-Navigation system and on-board electronic; 6-Radio equipment; 7-Scientific equipment; 8-Actuator of the wings; 9-Wings; 10-Vertical stabilizer; 11-Engines; 12-Central bloc of the GRD engines, pitching; 13-Steel frame.