The way I think about this is since it's NOT impossible for the CCP and PLA to have totally shrouded this project for the entire duration of its development phase including prototyping and test flights (you surely have to concede this possibility), therefore it is also NOT impossible for LRIP in 2023 (I don't know or even think this since that was a rumour after all and this H-20 topic is riddled with bad hints and rumours for years). Let's just play with that rumour and assume it's relatively official but ambiguous with wording on status.
Your entire argument on impossible and unbelievable rests upon the assumption that prototypes and test flights must be revealed years and years and years before LRIP. I agree that such things surely take place many years before LRIP and service but China's ASAT, nuclear program, AShBM, hypersonic weapons, to mention a few end platform projects, did not get their prototypes revealed at all. The AShBM and hypersonic weapons were observed by other nations through sea and space based sensors, over horizon radars etc but none of them were photographed, announced, or disclosed in writing before deployment and even then, probably some time after deployment. The naval railgun project's prototype was revealed years before completion. But all that means is we have precedent for both styles.
When it comes to H-20, it isn't simply announcing and showing prototypes of a new rifle being evaluated. It's a stealth strategic bomber with immense military and political implications and consequences. The further up this sensitivity chain, the more reason there is to hide such a program and only publicly reveal later rather than sooner.
Americans did not reveal B-2 until well after service. Same with the SR-71, stealth blackhawk, F-117. But there are also some prototypes and evaluation projects that were revealed like Comanche attack helicopter prototype and project, X-47B and so on.
These rumours are pretty questionable but it's certainly not impossible for H-20 to be in service and LRIP in 2023. So your reasoning on impossible with comparison to J-20 is throughly fallacious. But it must be said that your position itself may not be wrong! there is a distinction here! Not impossible also does NOT mean you are wrong. Can't stress this point enough.
Maybe language is a barrier here but basically I mean it's possible (but certainly questionable) that the the government and PLA (and of course XAC/AVIC) have hidden the entire prototype and testing phase like the equivalent of J-20 from 2009 to 2015 or so. That entire chunk has already happened just without all the wall climber photos and intentional reveals commissioned and planned by CCP. They can plan reveals and they can plan a hidden project.