Top half side of the screen is darkened.

Model: UN40F6300

I recently bought this television for $40 on Facebook marketplace from a guy with no reviews. Big mistake. He showed me it worked and it wasn’t that noticeable until that night. I’ve looked everywhere but haven’t found out a solution.
If you’re wondering if I use a DVR or cable box, I don’t, I use it for my ps4.

any suggestions could help.
thank you