Klan - Just to clarify your question…
It sounds like you have your NUC connected to your DAC (Devialet D200) now. Given that you tried a Jitterbug, I’m going to assume you connect over USB (vs. AES/EBU, TosLink, or coax). What it sounds like you are considering is a SOSE, wired network connected to the NUC, attached to your DAC over USB. Is that correct?
IMO there are too many unknowns and variables to be able to tell you with any certainty whether that will sound better. I’d venture to say that it is not possible to say things will sound better with the SOSE with any certainty. Likewise, in most instances, I think it’s fair to say it might. What we don’t know is the noise the NUC is contributing to your analogue gear (if it’s physically close to it), or what losses you are experiencing due to a long USB cable (if such is the case).
Were I a betting man though, if you’ve got a short, quality USB cable now, and if you have that NUC a meter or two away from analogue gear (and analogue cables), then you won’t hear much of a difference. But you might. Sorry knowing with certainty is not possible.
But I will share this thought with you…
I have no idea if my NUC - when it was on my hifi rack, USB connected to my DAC - contributed any noise or sonic degradation to my system. I never heard any. But I never listened for it either. So I guess that means it was not obvious. But I still got a SOSE and moved the NUC to another room out of precaution. In my case, that would not make things worse, and might have made them better. Again, never bothered listening for it. But in a music reproduction system where interconnects can cost more than a SOSE, it was an easy decision to make.