Yes Russia flew scramjets well before Zircon. But US also flew scramjets with HTV program even if most of the announced projects were failures they did have at least one successful scramjet flight before they cancelled their HTV and Blackswift program. Now replaced by FALCON (?) or whatever they're calling their HCM/reusable hypersonic air breathing craft.
China also flew scramjets in tests before YJ-19. Flying scramjets and mastering scramjets can be two very different things.
Even India might have flown scramjets in tests. They certainly have bench tested them at least.
Just because Russia does have one operational hypersonic air breathing weapon doesn't mean they're certainly ahead of the US or China. It may be the case but I have doubts.
The Zircon appears to be quite a low tier HCM. It looks like the Hyfly and Lingyun-1. Can we please stop pretending the Zircon is something like YJ-19 with a underwing intake?
Zircon:
View attachment 159269
Boeing Hyfly and Lingyung - 1:
View attachment 159268
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The Zircon's intake looks EXACTLY like Hyfly and Lingyun-1. Look at the Zircon launch picture. It doesn't have a HTV or X-43A or YJ-19 style intake.
Lingyun-1 and Hyfly both use engines that neither China or US call pure scramjet. Both nations call this some pseudo scramjet engine.
If China or US wanted to perfect this path of HCM, I suspect they could have. I suspect DF-100 (not DF-1000) might be using a similar type of engine, a halfway solution between ramjet and scramjet. Online literature for these weapons are scarce but we also know the HTV, X-43A and DF-19 have scramjet engines. They use a very different intake design. The pseudo scramjet uses a ramjet or rotating detonation radial style intake but with curiously identical shaped vane openings and geometry.
This perfectly aligns with what we know of Zircon from the available official photos of the missile (it has a radial intake) and from Ukraine's photos of missiles they claim is Zircon (either intercepted or whatever).
Hence I want to say that at least China is ahead of Russia in hypersonic propulsion tech since China has fielded even torpedo tube launchable scramjet powered HCMs. US I would consider to be ahead as well given the history of their programs, determination to field hypersonic cruise missiles and availability of resources compared to Russia. You can point to programs from the 20th century but you'd be remiss to think that China didn't also have hypersonic engine programs in the 20th century. They probably didn't show them as much as Russia/USSR. US didn't start playing with this any later than the USSR and had more resources than the USSR every step along the way. You can point to those programs but they may be Buran like.
Zircon ~ Lingyun-1 ~ Hyfly < YJ-19
If the above isn't true, why didn't China even field this style of "HCM" when they were playing with the Lingyun-1? Assuming knowledge and learning from that program didn't go into DF-100.