If that is true it just shows how the US cannot even make a cost effective design anymore. There is no good reason why an eight engine aircraft like the B-52 should have lower maintenance costs than a twin engine aircraft like the B-21. If this is attributable to stealth coatings, taped over access panels, and the like it only shows how stealth, at least how the US implements it, is a boondoggle and a massive waste of money.B-21 will be more expensive to maintain than B-52 or B-1 even with numerous improvements over B-2.
I omitted Russian bombers because I don't see them as a reliable factor in any future scenario that PLAAF could consider. PAK-DA is still theoretical. Tu-160 is at B-1 level (no matter what Russian propaganda claims) and Tu-95MSM will be at B-52 level approximately. Those are not assets useful in scenarios other than defense of own territory starting from 2030 onward.
Empty weight: 110,000 kg
Powerplant: 4 × NK-32 afterburning turbofan engines, 137.3 kN thrust each dry, 245 kN with afterburner
Maximum speed: Mach 2.05
Empty weight: 87,090 kg
Powerplant: 4 × GE F101-GE-102 afterburning turbofan engines, 77.4 kN thrust each dry, 136.9 kN with afterburner
Maximum speed: Mach 1.25
Tu-160 has nearly twice the thrust and speed. Thrust and mass fraction directly relate to bomb load in such an aircraft.
As for the PAK-DA it has been funded, they are building two prototypes, and the engine is in the test stand. At this point it is about as theoretical as the H-20. The H-20 should come out earlier since it likely will use existing engine designs and the program was started earlier. H-20 will massively increase Chinese capabilities vs H-6K with regards to bomb load, range, penetration capabilities. It will be a quantum leap forward while B-21 is a downgrade in terms of capabilities from B-2. B-21 is basically a cost reduced version of the B-2. The main advantage is it is expected to be produced in higher numbers. As a B-1 replacement the B-21 will likely not have improved bomb load, will have lower maximum speed, and might have higher range and loiter time.