Unless H-20 is like a insanely massive like never seen before massive bomber, I doubt it could fit the type of missile they are talking about. They are talking about the Beijing sledgehammer type missile, the kind H-6 could only barely carry.
But I doubt they have actual info on this and is basically their speculation
Personally, I don't think the H-20 is going to be
that big (and I mean the
Tu-160-kind of big).
Speaking of which, the H-20 likely doesn't have to - And that the H-20 likely doesn't need to carry the Beijing Hammer missile either.
Given that we've already seen the YJ-17, YJ-19 and YJ-20, where all three are UVLS-capable - Therefore, if the H-20 has long enough IWBs to fit the air-launched variants of these missiles for land-attack/nuclear-strike purposes, then it should be broadly sufficient.
Per my previous guess-timations - The Beijing Hammer is about 13-16 meters long, whereas all the UVLS-capable YJ-17, YJ-19 and YJ-20 are below 9 meters long. Hence, the dimension difference between the two missile types is actually pretty vast, so to speak.
Which means the H-20 would only need IWBs that are ~9-10 meters long, instead of having to cram a ~14-17-meter long IWB in order to fit the Beijing Hammer.
This is also coupled with the advantages of launching at higher altitudes and at (high-subsonic) speeds (meaning achieving longer strike ranges than their surface-launch counterparts), alongside the VLO + ECM characteristics of the H-20 itself (meaning being able to get closer to the enemy targets than the H-6K/J/N ever could before dropping payloads).