The DEQX HP-5 looks an impressive piece of kit - I’ve just looked it up!
I see it is Roon Ready, so I am I right in assuming you are using in that mode connected via Ethernet? If so, you need to note that you can only group devices of the same type/protocol within Roon, eg Roon Ready (RAAT), or Sonos, or Chromecast. You can’t mix them. I could not see any reference on the DEQX website to it being Chromecast compatible; I think you may not be able to group it except with other Roon Ready (RAAT) devices.
My normal listening is through a Roon Ready Naim streamer; however it also appears on the network as a Chromecast device and I could group this presentation with other Chromecast devices on the network. Unfortunately that doesn’t help me sync it with the Sonos Play 1 in the kitchen, so I have retained my old Sonos Connect feeding the Naim via toslink. Unless I’ve missed something in the spec, you may need to do something similar.
Is the Sonos analogue output better than CCA? I don’t know. I’ve heard both, but in such wildly different systems that I really can’t compare.