So TCL will not help me at all because my hardware problems started just under 2 months after the warranty expired. Can someone help?

I have a 65R646 . I've disconnected everything external except the power cord. The TV shuts itself off shortly after starting. It gets shorter and shorter uptime (from a few minutes to a few seconds of just the logo). removing the power cord and waiting a few minutes resets this timer to a few minutes but it then repeats the pattern. I have tried a different outlet and not using a power strip

I've got all sorts of screenshots (inlcluding a status page) and video. I've tried a factory reset, making sure i have all the updates installed, and toggling a few settings. I've given all this info to TCL. They wont give me any hints on what might be wrong. I'm no stranger to a soldering iron if theres a common problem or an area to look in.