@gfunk550
I will first just assume you have added the (factory reset) Roam successfully via the ‘Add Product’ feature in the S2 Sonos App ‘Settings/System’.
Power off the Roam fully with a 5+ seconds press on its rear power button until you hear the shutdown tones.
Fully close the Sonos App (slide off screen) and reboot the controller device whilst standing near to the main router.
Whilst near your router (within 6 feet or so) then power on the Roam and see if it now appears in the App when it’s opened.
If not, then check your router and ensure QoS/Airtime Fairness are not enabled. That the router supports Multicast & Broadcast Data (IGMP) across the LAN and that either of the WiFi adapters are not isolated from the other network segments (that’s if the SSID’s are the same) and also check that the DHCP server is enabled and working and has addresses available. (reboot the router too, if necessary).
See if that then fixes your issue.