I have used mac mini with Roon, Auralic Aries G1 and Lumin U1 Mini with both native software and Roon as well as Tidal Connect, Bricasti M3 DAC internal network card as Roon endpoint and with Mconnect, and am currently using Aurender N200 streamer with both the native Conductor and as a Roon Endpoint. Not only do the streamers sound different, using the native processing on Auralic and Aurender sounds slightly better than Roon. Tidal connect and Mconnect sound slightly harsher/more “digital” to me than either Lumin native app or Roon.
I agree streamers don’t have a sound unless you drop them on the floor or hit them with a hammer. They sit there quietly and process the incoming data stream.
To understand why streamers or even the native processing vs. Roon sound different you need to spend some time reading, researching and understanding different designs and why a certain design decision was made, as well what in the streamer design and implementation influences sound quality. How certain designs are optimized for USB and others are optimized for SPDIF and what makes a difference between USB and SPDIF.
No one here owes anyone any explanation. Do your own ground work. And when ready, once your system reaches a certain level, you may want to compare few different streamers to hear it for yourself.
Saying a component in a signal chain doesn’t influence sound of your system is just not a good look.