Also clean those connections. The following video APPLIES! Watch where they clean the connection.
https://www.youtube.com/watch?v=G8777AzTf8U

It is possible it's the LCD but to figure it out you have to swap those cables out and do the work. Can be upsetting for those that want "only a guaranteed solution." Some LCD panels integrate the timing and control boards so that's expensive to replace.

That said, I caught the Amazon Prime Day Fire TV (by Toshiba) for a 50 inch Fire TV delivered to my door for $312.46. I wonder how much has been invested in repair on this set?