@Rbabel According to pictures on the Internet the "Smart Wifi SW10A" should be a rectangular-shaped device, not the white Wi-Fi disc I was referring to. And sellers of the Smart Wifi SW10A do note...

@IndyMike Hi, "Firmware" refers to a certain type of software. The hardware version of the router can only be up- or downgraded by replacing the hardware. So, you would need to return the AX21 V4.6...

@Angela2904 Could you please post a photo here that shows what is displayed on the small LCD screen of the M7350?

@Alex_Led Can you find an Ethernet outlet inside the house that is similar to the one in the office? If the previous owner had his Internet router inside the house and a working Internet connection...

@Alex_Led Ok, that would mean there is no physical connection. Please verify that the Ethernet cable that is going from the living room to the outside office is securely plugged into one of the LAN...

@salam09 Network names in the format "TP-Link_1234" are commonly the default Wi-Fi names of TP-Link's Wi-Fi routers. TP-Link range extenders will not show something like this after a reset. I guess...