Where next for my system?

[rsegato]

The primary objective should be to minimize the number of cables connected to the Devialet units. The Mac Mini should operate with only the essential connections: a power cable, Ethernet, and a single USB output — nothing more.

The next step is to optimize the streaming source. There is inherent translation latency when using ports routed through the CI board, so these should be avoided. The most direct and effective strategy is to feed the Devialet via a single coaxial or XLR connection. In this configuration, the Devialet would require only a power cable, one coax/XLR input, and speaker outputs. If possible, disable both Wi-Fi and Ethernet to reduce potential noise ingress.

To achieve this, the missing element in your system is a high-quality streamer. While the Holo Red Streamer is a strong option, IanCanada offers streamer/DDC solutions that are both more cost-effective and, in some cases, superior in performance. I am currently evaluating these options myself, and you may wish to conduct a similar assessment before making a purchase.

Regarding loudspeaker changes, your current system already delivers full-range coverage. Moving to a B&W setup at this stage would be largely an aesthetic choice, as your existing combination of high/midrange speakers and subwoofers provides excellent performance.

For a truly substantial improvement in sound quality, the next priority should be room acoustics and/or digital room correction, as these will have a more profound and measurable impact than changing speakers in your current configuration.

I like this summary of the "primary objective" being minimal 
... so adding along the lines of the "missing element" high quality streamer and trying to get an inexpensive streamer with AES/XLR digital output 
(I've yet to try XLR in to my D-Premier which this forum generaly has people saying it is preferred input)

Schiit Audio has released their EITR 2 which is a DDC with XLR out. 
It's a mere 99$ USD so this "frugal" upgrade path is where I'm heading.
Schiit doesn't formally state jitter but online they said they did get a low result via an "APx555 the other day for a quick and dirty test and got a result of 74 picoseconds."
It is 24/192 bit perfect capable with 110 ohm Output Impedance.

My plan :
1) Roon Nuc source streaming to Fiio SR11 (99$) via Wifi in (one could go ethernet in but thinking Wifi is better noise wise)
2) then Fiio SR11 USB out to this Schiit EITR2 USB in
3) then Schiit EITR2 XLR out to the Devailet AESEBU XLR in 
... hopefully a clean and cost effective and timing aligned digital AES/EBU XLR feed for $200 USD

Note I have a second hand (50$) dual 5V LHY Linear power supply so the SR11/EITR2 combo will both be fed a clean 5VDC supply to hopefully keep the digital input to the Devialet good.  

I will try and post back results for those interested on XLR in as above vs SPDIF quality from same SR11