@huitong is right to cast doubt on the status of the H-20 program as a result of the emergence of what we're now calling the GJ-X.
However, there's also the
possibility that what we have
before us is in fact the product of the H-20 program or what the original H-20 program
transformed into. A few points to consider:
1. The H-20 is or was a XAC program, and there are only so many entities in China reasonably capable of designing and manufacturing a combat aircraft the size of the GJ-X.
2. IIRC, in the last year or so, at least a couple of reasonably credible or popular Chinese sources have claimed that the H-20 would soon be unveiled in some capacity, and here we are.
3. For years, just about everyone expected the H-20 to be a subsonic flying wing — comparable in size to the B-2 or perhaps the somewhat smaller, but newer B-21 — and the GJ-X appears to align with those parameters, even if it's uncrewed.
4. A lot of folks expect or expected the H-20 to be some sort of intercontinental bomber, but that was never confirmed as a PLAAF requirement for the H-20. However, the need for the H-20 — or something else stealthy, survivable and reasonably sizable — to replace the legacy H-6 is almost certainly a PLAAF priority, and the GJ-X fits the bill.
For now, there's no reason to expect the GJ-X to be ultimately designated the H-20 or WH-20, however
amusing such a scenario might be (granted I laugh at just about anything and everything).
Regardless, the GJ-X checks multiple "H-20 boxes," and if this prototype was built by XAC — which is rather plausible — it likely
at a minimum benefited significantly from the H-20 program's R&D.