They supposedly already had a JH-XX in the works, so maybe they just shelved the H-20 and focused work on the JH-XX instead. Rather than a H-XX, such a plane can not only sneak up on enemy aerial targets but also get away in time. A B-21 or H-XX can sneak up on a high value aerial target, but it may not get away from the escorts which will try to hunt it down.I think the reason the H-20 is being delayed for so long is because they looked at the CAC plane and went back to the drawing board. I would be surprised if a flying wing is going to be selected as the final H-20.
On a side note, I wonder if the eventual evolution of aerial warfare will lead down the same path as the ground warware we're seeing in Ukraine. That is, with stealth negating stealth and eventually robust self-defense measures, that we'll go back in time and fight air wars like in WW2, with dogfighting, speed, and altitude ruling the roost with an added twisted of drones.