Has Anybody Had Success Going from Ethernet Streaming to USB Streaming?

Why would you want to move from Ethernet to USB? Serious question. I'm building a NUC based server at this time as well. Understand that noise may be an issues, but isn't it easier to eliminate noise then try to fix USB clock issues?

Not sure what this is about but I went from  Synology NAS via WiFi to portable SSD via USB A into a streamer, i2s out
The USB experience in this case sounds better and is much more convenient . I can load tracks via WiFi faster and I don't have to remember to run FolderSort.
As far as the question I know nothing of this NUC you speak of and I've never heard of linex.
It sounds like you have way more than you need to play local files.

I have recently made this kind of switch, but I also added a new component that makes a big difference. 

I was using a Roon ROCK NUC, through an EtherRegen to a Bryston BDP-2 streamer and then via AES to my Terminator DAC. I tried connecting the NUC directly to the DAC via a high quality USB (AQ Diamond) and I thought the Bryston sounded a bit better (but it wasn't dramatic). 

This past week, I received a Denafrips Gaia DDC. I removed the Bryston from the system and connected the NUC directly to the Gaia using the USB cable. Initially, I had the Gaia connected to the DAC using the same AES cable. This was somewhat better than using the Bryston, but wasn't dramatic. 

Then I hooked the Gaia to the Terminator DAC using a cheap HDMI i2s cable. This improved the sound quality significantly, even though the HDMI cable was less than 1/10th the cost of the AES cable. I've got a high quality i2s cable on order, but even with the cheap cable, the Gaia/Terminator combo connected to the NUC via USB was a significant improvement over using the ethernet streamer. 

The Gaia costs about $1700. The Bryston streamer I was using retailed for almost twice this cost. It's no longer a current model, but the BDP-3 that replaces it (and has the same digital audio output circuitry) retails for $4100. So if you are looking for something to use between your NUC and DAC (no matter what DAC you are connecting), and don't need to have these connected over ethernet, I'd recommend taking a look at the Denafrips Gaia (or their lower priced DDCs). 

@jaytor Thanks for sharing your experience. I had my Sonore Optical Rendu streamer feeding the secondary 2-channel system in my home office. A couple of months ago, I moved the Sonore to the primary system in the media room, and using Chromecast in the study as a stopgap measure until I buy a better streamer. I was thinking of buying another opticalRendu, but I find your opinion of the Gaia intriguing. Probably need to do a bit more digging. Thank you for sharing.

Ratbastrd... love the handle.  The NAS is slower than a NUC in loading and accessing files.  Some say the NUC running Linux is designed specifically to stream music only and doesn’t run extraneous applications in the background like a windows based NAS.  USATube Audio who is the distributor for Ayon in the USA offers their Roon Rock Server and they claim their server is a sound improvement.  I’m trying to see if anybody on the forum took that route and what was the result.  Based on the generation of my S-5 with an older Ethernet input, I am confined to taking the USB output from their Roon Rock, using the DDC to covert USB to I2S so it can be used by my Ayon S-5.