There is one other factor I would add on your question of lumin vs sonore. Today I began testing a brand new feature just added to my lumin devices via a firmware update called Leedh volume control. There is a whole active topic in the Roon forums on this here: LUMIN Music - Leedh Processing
Leedh volume control is in theory bringing lossless volume control to digital devices and Lumin is one of the first ones to implement it. It’s getting really good reviews and many think its superior to typical preamp analog controls – even very high end ones. Of course YMMV.
But utilizing this feature allows you to turn on “Device Volume Control” in Roon and have it control Leedh in Lumin. By doing you can if you choose have your DAC output go directly to an amp and eliminate the need for a preamp thereby simplifying the audio chain and (of course again YMMV) improving sound quality.
In one of my setups I was going from my U1 to Dave/Blu and using Dave’s preamp for volume control. Since Dave wasn’t roon ready, Roon could not control the volume which made me have to use another handheld remote for volume control. With Leedh in my U1 I am able to put the Dave in DAC Mode, thereby bypassing the preamp controls in Dave and going directly to my amp and utilize volume control in Roon. Although I’m still testing, my first impression it is a slight improvement in sound quality and I really like having the volume control in Roon.
I note this for you as this is another + in the column for the U1 vs Sonore but whether it’s useful for you will depend on your setup and your qualitative judgement of sound quality …