LG 43LH600T Wi-Fi not connecting to the Wifi

Hey everyone,

I need some hardware/software insight on an LG 43LH600T smart TV (running webOS 3.0, manufactured around 2016).

The Context: For years, this TV sat in the living room strictly connected to an external set-top box via HDMI; the built-in webOS smart features and Wi-Fi were completely unused.

The Problem: The TV perfectly scans, detects, and lists all the surrounding Wi-Fi networks. However, the moment I select a network, enter the password, and hit connect, it instantly fails with the exact error:

"Could not identify the reason for failure. Please check the status and try again."

What I’ve already ruled out:

• 2.4 GHz vs 5 GHz Band: I know this older model doesn't support 5 GHz. I tried connecting it to a dedicated, isolated 2.4 GHz network, but it still throws the exact same error.
• Wired Connection: I ran a physical Ethernet cable to it, and the wired internet works flawlessly. I used this connection to successfully run a complete system software update, but the Wi-Fi issue remains.
• Basic Troubleshooting: Deep power cycles (unplugged for 5+ minutes, held down physical power button), manual time/date settings, changing country and also reset the TV.

I cant connect it to ethernet since my router is in different room. Gemini suggests either to open the back panel and inspect the wifi ribbon or to buy a firestick.

Does anyone have any suggestions to try.