If anything, a longer Ethernet cable might be better than a short one as the voltage drops with length, and so any noise it carries will drop proportionately. If there is any discernible effect, I would expect it to be on the streamer rather than the NUC, as that’s where any noise might couple into the analogue electronics, so in your case probably not an issue.
Whether this makes an audible difference at all is another matter. For most, I would say it’s something that’s not worth worrying about.