One thing to look out for in Roon are your settings. Turn off volume leveling, if it’s on. I have also heard Roon sound compressed but only when leveling was enabled. Also make sure you’re using fixed volume, particularly if you’re not doing any upsampling. If you’re connecting your computer directly to your DAC, try a DDC in between. Or better yet, get a separate streamer so that Roon is running as a server and the streamer as a transport. Then connect the streamer to your DAC with the best connection for your particular DAC.
I don’t doubt that people hear differences in software or hardware being used but make sure to remove some of the settings differences as variables.

