Mind you that diagnosis is key but exposes LETHAL VOLTAGES.

-> https://www.youtube.com/watch?v=oE6K4xBVweA

And a video of your TV's failure is fine but won't be what any tech will use except to verify it needs service.
The failures are common, a too long list and is not Samsung exclusive so you'll see all the other makes at 5 years.

Get an estimate.