Simply to answer your questions...
The AV20 has been solid. Initial Audyssey setup and curve editing worked per usual App experience and overall quality of my experience on the AV20, post room correction, has been very good.
I cannot and will not make claims of night and day differences between my older SR6012 purchased new in Summer of 2018 when it was on closeout for the newer models. However, the processing power in the AV20 is significantly improved over what was in a mid-tier AVR designed and manufactured 8 years ago.
What I am willing to say is that the Movie and Gaming experience has been more impactful. Audyssey on this machine measured differently than it ever did on my 6012. Is it the XLRs or the machine itself?

No other equipment was changed.
As to Music only, I have had precious little time to sit and enjoy anything in an active listening session. What I have listened to is solid. Nothing notably off in any way. Keep in mind I refuse to make claims about being able to hear the possible drop in noise floor or improved SINAD/Distortion numbers. But what I have listened to in a more passive manner has been great.
Lastly, I am not one to assign magical properties to capacitors. I know some love to discuss Caps and their "qualities," but I am more firmly in the camp of Caps and other wiring not really affecting SQ.
With that in mind, I don't think we have seen any 3rd party bench test of the AV20 yet, however Masimo/SU/D&M know that somebody will likely put this on an AP and run it through its paces, so my money is on this thing testing as advertised. Or at least close enough.

If that is the case, it should test higher than the AV10. *shrugs We'll see.
Is the AV10 worth the new higher price? Possibly for those who can afford it and want the true flagship model.
If you don't need the 2 extra channels, I don't think the AV20 will disappoint.