@Jacques_Distler. There are quite a few examples of rf noise being problematic and something to avoid in ethernet and other audio cables specifically because it can affect the analog output.
It’s why Rob Watts recommends ferrites to be placed on BNC cables for Chord Dave/Blu. Here’s the thread if you want to read it: https://www.head-fi.org/threads/chord-electronics-dave.766517/page-711
It’s why both Lumin and Sonore are now putting optical network connectors in their streamers. I would expect these to be standard fare in most if not all high-end streamers in the near future specifically to prevent this.
Whether you have a rf problem in your setup depends on your setup and of course that affects whether you have an issue, but the problem does exist.
Could go on, but you can find examples of this from reputable sources if you search.