Hi @Hector_G are you sure it’s a network connection issue? If the content’s on a local SSD then that makes little sense as you’ve tested the network connection and tried different cables and the like. Do you have a USB DAC that you could connect directly to your NUC? That might help isolate the issue as it removes the network. If it’s not the network I wonder if your NUC is overheating and throttling, SSDs can overheat as well. What case and NUC are you using?
edit
I see it’s an 8th gen i7 so will need some keeping cool, is it the standard case? Also what make is the M2 and is there still plenty of space on it?
Finally, it may help to restrict posting to a single thread: Issue with Roon + Qobuz + NUC 