I have to suspect that this is all related to the increased power of the DAC in the AV 10.
You shocked me, like with 50 kV, for even thinking it is the DAC!!!!!!!!! Of all people, I would have though you know what DACs do right?
By the way, it is a fact that the AV10 use a reference class ESS DAC IC, but not the flagship class that is used in some other AVPs/AVRs such as the Anthem AVM90, but that's irrelevant for this discussion anyway.
The DSP is a different story, D+M upgraded the IC to one that has sufficient capabilities to do not only the increase channel counts from previously 15 to now 19, but also has to do the paid upgrade Dirac Live Bass Control plus Dirac Live ART so there is just no comparison.
With all that increased raw processing capabilities of the Griffin Lite chip, it should not be a surprise you are so much more impressed with the AV10's Atmos performance vs the AV7705'.
Just a side note: credit to D+M, they have done it again, leveraging purchasing power, by filtering down such improvements onto the lower models, even the Denon 3000 series and Marantz 50,40 use the same DSP IC, so I would say those on a tighter budget, can expect superior Atmos performance too by simply going with the X3800H or Cinema 50 AVR, yes, AVRs.

Those AVRs also use the same preamp/volume control IC, and most of the opas as the AV10, but of course the AV10 has superior wiring scheme, layouts, shielding and the better HDAMs etc.