My 50” TLC 4k hdr power off and on by its self been doing it for about a yr and it does for days at a time it’s only 2 years old it was only a year old when it started power off and on I don’t knw what’s going on with roku but I’m getting tired of taking 6 hrs to watch a movie
Have you tried to contact TCL? They may just point you back to Roku who may just point you to TCL.
Where can I get support for my Roku TV™? | Official Roku Support