Why not just a flying boom anyways then? Plus for large aircraft it'll be really difficult to refuel via drogue due to bad manuverbility, it'll alot easier to have just have such a aircraft fly into position behind the tanker and then have the boom operator do the work of alignment. H-20 might have a issue where you could position the refueling probe considering you ideally want a decently long probe for very large aircraft and have it positioned near center which is an issue for flying wing aircraft due to having tiny noses.
IMHO:
The Boom method is considered more expensive and less flexible. You need a more complicated device that needs an operator and you need the receiving aircraft to include a receptacle system built onto the top of the fuselage. Because it is most efficient with larger aircraft you need to put that receptacle in the forward third of a large aircraft with the boom reaching over the cockpit which creates some anxiety especially since it is mainly out of the receiving pilot's hand and dependent on the boom operator.
Most air forces, outside the USAF, use the probe and droge method. From what I read, pilots in general prefer the probe/drogue way of refueling because of the fkexibility and control.
For existing aircraft that were not designed for air refueling like those based on the Y-9 platform, adopting the probe/drogue method is supposedly far easier than reworking the new variants for a receptacle.
I think using boom method which PLAAF had never used and which really is only widespread in the USAF (USN use the probe/droge exclusively) posed a lot more risk with the current aircraft they and they've already shown what they are using going forward:
That said, maybe they'll experiment with the H20? But it is unlikely with variants of their current inventory.
