This has been mentioned a number of times in other threads before - Roon is designed to have separate devices for the server and endpoint. I have found that using a streamer separate from the server does improve the sound quality. But what made a bigger difference was using a DDC that buffers the data from the streamer and delivers it to the DAC over a synchronous interface.
As I understand it, Roon sends the data in fairly large packets and unpacking these packets in the DAC requires additional processing power which can adversely affect sounded quality. Handling this process before the data is delivered to the DAC seems to help.
I can hear no difference between Qobuz through Roon and using Qobuz connect on my system.

