This just for internet connectivity, not other connections. As an alternative to Wi-Fi.
For TV and media box (two devices) that you wish to each connect by ethernet for internet connectivity to these devices, you can probably get away with an ethernet splitter.
Pro 1: no extra ethernet cables needed all the way from the router, just short extra cables from the splitter.
Pro 2: no extra power adapter needed.
Pro 3: cheap (~$8)
Con 1: just two devices supported
Con 2: support for ‘Fast Ethernet’ (<100 Mbps) only. The TV and Apple TV will be somewhat limited in speed, but still good enough for all TV streaming content (4K HDR will normally be <25 Mbps).
A more elegant ethernet-only solution is an ethernet switch, which typically has more ports available, does intelligent routing (doesn’t send a signal to devices that don’t need it), allows for better network speeds, but needs its own power adapter.
I have an 8-port ethernet switch near my main AV setup, with currently 5 ports utilized.
Ethernet switches come in two flavors: managed and unmanaged. Unmanaged is less complex, cheaper, and most home users do not need managing (setting rules for devices).
Prices go up by number of ports (and build quality: plastic vs. metal casing). A compact unmanaged 8-port ethernet switch can be purchased for ~$22.
