We're sorry to hear about the issue you're experiencing.
Have you tried contacting the TV manufacturer to inquire further? I'd suggest starting there to see what options or suggestions they can provide. Each Roku TV manufacturer provides direct support and warranty services for their products running the Roku OS.
Mine does this as well and I tried everything you did. Customer support did nothing and cancelled my service inquiry after 4 days. Does anyone have alternative solutions? I won't be dealing with TCL any further. They've lost my custom. Good luck