Since the Soundbar is brand new, I would simply return it if not seeing any networks at all (not even neighbors).
Normally, if just not seeing your network, but seeing others, you can check a Roku's device connection ability by attempting to connect it to a mobile hotspot if available. If it can connect to a hotspot, then generally verifies that something is wrong with the network setup.
If the Roku device fails to see the hotspot as well as any surrounding networks, then indicative of an internal failure and needs replacement.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660x, Premiere+ 3921, Express 4k+ 3941