Just view a few of videos to learn about the power issue and you may recognize some other clue or occurrence that may confirm that the problem is the power supply. Or recognize some viable fix you can safely do on your own.
Not suggesting nor saying that you must or should attempt the repair per se. And, unless you have made similar repair in the past you should not try to do so on your own.
Find a knowledgeable family member or friend who can help. Or take the TV to a repair shop.
You will at least have some knowledge of the part's cost and the labor involved. A new TV may be less expensive.