Fake? Maybe.
ZH shows a supposed test of our answer to Russia's hypersonic missiles,
First and most obvious, the missile is sitting on a test stand. There's no way of knowing how fast it can go. It's just shooting out a flare.
Second, the rocket is in the middle of a big field of grass or ground cover, which looks fairly dry. A cigarette can start a brushfire. This huge superhot flame was presumably running for several minutes, radiating heat in all directions. No sign of charring, no brushfire.