I too am a Roonaholic.
When I first started with Roon, I had my Roon Nucleus with Sbooster LPS streaming to itself feeding a Chord Qutest via Curious USB cable. It made for an enjoyable combination. A few years later I acquired a Bricasti M5 network bridge acting as Roon endpoint, and had that feeding the Qutest via Kimber D60 Coax, and to my ears this made for a significant jump in sound quality. I then upgraded my DAC to a Rockna Wavelight, and this notched things up once again. Earlier this year I replaced my Bricasti M5 with a Hifi Rose RS130 utilized as Roon endpoint. And again enjoyed a significant boost in SQ and audio enjoyment, first via the Kimber D60, and now via Tubulus Consentus I2S cable into the Wavelight. Then last month introduced a Melco S100/2 network switch into the mix. And was able to notch things up yet again. Currently the Melco and Rose are connected via RJ45 terminated ethernet cable (Wireworld Starlight Cat 8). But both the Melco switch and Rose RS130 support fiber, and I do intend to experiment with fiber in the future. Bottom line, in my own experience, found the streamer to be a major piece of the puzzle with respect to sound quality.