Thank you very much for the quick tips 🙂! In fact, the description on tuxone is really “a work of art”… wow. I need a little time to get used to it. Also the tips for USG configuration. A bit demanding for a hobby networker 😉.
The main message that I take away after a quick glance is: Swisscom TV-Box to either connect directly to the Centro Internet box (pulling my LAN cable as described) or to virtually “loop through” the connection via the VLAN construct through the USG, which I honestly do still have to take a closer look at it (effort and future maintainability of this configuration solution if the Internet Box or the USG undergoes firmware upgrades, etc.).
You have encouraged me in my approach and put me on the right track. Thank you very much for that!