There seems to be a generic challenge with Roon Bridge on (Raspberry Pi) Linux systems. Roon uses ALSA, and ALSA seems to have problems with asynchronous high rate DACs (edit: see below).
I have tried Rasbian on the PI B and the B+, and Ubuntu on the Odroid C2. I see many posts in forums about dropouts or even just noise at sampling rates above 48 kHz on USB. Sometimes this can be hardware (especially on the Pi B, with its shared bus), but there is a fundamental software issue which seems to be that the ALSA subsystem is not designed for 1) higher than 48 kHz on USB, and 2) asynchronous USB, which would require a different driver approach. At least this is what I gather from experience and browsing many forums.
In particular, Roon Bridge loads and works fine on Pi B, B+, and Odroid C2 (armv8 version). All three have the same observable problem of pops and garbling at 176 and 192 rates. I have checked and eliminated any network issues, and in particular, on Ubuntu on the C2 I have monitored CPU and network usage while streaming-- both low. Roon reports no problems.
What are the solutions? Custom drivers would work of course, and may be why custom Roon Bridges and appliances work fine, but what is available off the shelf and open source? Does Dietpi work for this situation? I see it is going to push higher on the HDMI interface, but how about USB? Anything else? I see lots of random tweaks of configs, but they seem to work by accident if at all.