Any of your SuperPods can be connected to your modem/router to act as the Gateway pod since they are identically manufactured. Either port on the original SuperPod can be used for the WAN connection.
SuperPod with WiFi 6
For the best performance, a SuperPod with WiFi 6 should be the Gateway pod if you have one. When plugging in a SuperPod with WiFi 6 as the Gateway pod, the left Ethernet port (globe icon) is the designated WAN port and is capable of 2.5 Gbps.
Ethernet ports for LAN connections
Each and every Ethernet port on your pods can be used as a LAN connection to hardwire client devices that you wish to connect to with an Ethernet cable. The left Ethernet on a SuperPod with WiFi 6 will negotiate at 1Gbps when is as a LAN connection.
Mixing pod types on a network
If you have a mix of different kinds of pods, always choose the highest performance pod as the Gateway pod.