Roon likes pared-down Linux boxes dedicated to Roon. I had an Auralic Aries G2.1 and their implementation of Roon is terrible. They have a big bloated operating system tuned to work with their badly designed smartphone apps. Their implemenation of Roon is an afterthought, and it did not sound good.
I switched to an Allo DigiOne Signature running Ropieee (an extremely pared Linux purely dedicated to Roon) and a Roon ROCK server on an Intel NUC (following Roon's excellent instructions to put it together) and my system sounds amazing. Very very detailed, huge 3D soundstage, wonderful tonality, and bass tone and texture that has been a revelation.
I just moved from a Benchmark DAC3 to a Holo May KTE DAC and the improvement is fantastic. Roon is not limiting my ability to improve the sound in my system at all.
I think the problem is that Roon has done such a good job of making Roon work on bloated non-Linux systems and Swiss army knife Linux systems (like the various embedded players in stuff like the Auralic) with sloppy implementation that the bits-are-bits crowd assumes that anything that runs Roon will run Roon equally well. Roon is designed for pared-down Linux. It sounds incredible running on these tiny, free Linux distributions (Roon ROCK and RoPieee). The Roon Nucleus that Roon sells as the canonical Roon server is just an Intel NUC running Roon ROCK in a very nice fanless case. For half the cost you can put your own together.
Here are measurements of Roon feeding various endpoints and DACs, for those curious abou the measurement side of the story: https://www.youtube.com/watch?v=Jvu_doQfAI0