The one I referred to is a TCL 55S405. It seems the only solution is to never connect it to the internet, or factory reset it and never connect. Once connected if you remove the network details, it will blink indefinitely (at least for many TCL models).
Amazing that their budget recommendation is the Roku TV. I can tell you from experience if you don't connect them to Wi-Fi there is an LED that will constantly blink on the bottom front of the TV, with no way to disable in software. So unless you like your TV with an electrical tape aesthetic, I would avoid Roku TV's.