NAA doesn’t need internet connection, just HQPlayer.
But my recommendation is to use these things as designed - connected to a regular home network, through a proper 1 Gbps or 10 Gbps switch that has at least following features:
802.3x Flow Control support
802.1p CoS/QoS (advantage if there’s DSCP/DiffServ support)
802.3az Green Ethernet as optional extra, but highly recommended
Switch would be star-point where everything else, including router is connected.
In my case, I have one “core” switch at the central patchbay where cabling to each room goes. And then a room specific switch in each room for local network distribution where each network connected device is connected to. These switches are by Cisco and HPE (aka Aruba these days). In addition, I have two Aruba WiFi6 wireless access points powered from the core switch through PoE. These provide wireless access to the network.
This allows me to for example reliably stream 8-channel DSD256 over WiFi to an ethernet connected NAA endpoint.
P.S. Note that if you use a smart L2/L3 switch - these are not plug-and-play devices, but need to be configured correctly to perform properly in this kind of environment. I have for example Cisco SG-350 series switches, but these need some configuration (and firmware update maintenance).