I definitely do not claim expert status on these matters.
I do, however, ask myself frequently about my own goals of building out .4 Atmos in my room, and how I would adapt to processing that.
Different, of course, from chasing sound quality. But similar in terms of how/when do I upgrade my SR6012. I can use this as is but am limited on recommended placement for those Tops or Heights. I can upgrade to something like the HTP-1 that will give me much greater freedom in speaker selection as I understand it, but for a significant price. That price also includes Dirac which is arguably the best at what it does, even over Aud XT32 below the Schroeder Frequency of my room.
Of course, there is one of the possible areas you could see improvement in upgrading to a more current AVR in the Denon or Marantz line. The 4700 from Denon would be comparable to the SR70xx line and you would see some improvement I am certain, considering the changes in technology over the last 13yrs since the SR7002 came out. In switching to pre-out mode exclusively and using external amps, you would realize the cleanest possible processing of the signal going through the machine as evidenced in the ASR reviews. XT32 would give you far greater control over room correction if you employ it at all: coupled with the Aud App, you can set a curtain to limit the correction to below 300-500 Hz only. Again, an improvement...
But how much?
For how much?
Sounds like you are on top of it pretty much. Perhaps just planning now for that upgrade in another year or two as HDMI 2.1 actually gets ironed out and sees more necessary implementation?