Since YJ-19, in fact all the hypersonic glide and cruise missiles displayed outside of DF-17 which is suspected to make an appearance again, is a naval VLS launched HCM, this would indicate land and air launched HCM have been around in China for some time.
Naval VLS launched HCM is the last and most difficult one to do. Land based is arguably simplest followed by air launched which admittedly has its own unique challenges from launch parameters but naval VLS heavily restricts all design parameters of your HCM.
Yes the Russians claim Zircon is a mach 8ish HCM. The Ukrainians have intercepted at least one Zircon with reasonably solid evidence. The Zircon looks like a Hy-Fly style scramjet intake. It's no doubt very capable and sophisticated weapon. I don't want to take anything away from Russia.
Guess what this means for PLA and PLAAF launched hypersonic cruise missiles like the YJ-19? There must be land and air based HCMs. Possibly what the insiders are suggesting when they say the true killer weapons aren't even being displayed. Land based could potentially even be hypersonic glide cruise missile.