Bought 2 tv’s. First one setup fine, no issues. Second one will not connect to WiFi. Does not show all available networks in search queue. Even adjusted network settings in router to disable password protection. Still won’t connect to an unsecured network.... bad network card. Unable to preform software update as there is no Ethernet connection available on device.
Try one thing first. In the settings menu there is a Network Connection Reset. I can't say exactly where it will be in your menu, but likely somewhere under System. This removes all network configurations, and can sometimes clear a corrupt setting that is interfering with the WiFi. I can't promise anything, but it's one thing to try.
But I will say that sometimes even new it might be defective. I brought home an Insignia Roku TV, and had all sorts of problems, finishing up with it stuck in the setup more unable to continue. I took it back a got a new one, which has worked fine for over 3 years now.