Hello! It sounds like your Smart TV may be experiencing a hardware issue, possibly with the display panel or the internal components. The fact that it started with a small circle on the side of the screen that grew into a scratch, and now the screen is completely white then black, indicates a progressive problem.
To address this issue, you may need to have a technician assess the TV to determine the exact cause of the problem. The cost of repair can vary depending on the extent of the damage and the specific parts that need to be replaced. In some cases, it might be more cost-effective to replace the TV rather than repair it, especially if the repair costs are high.
If you can provide more details or a screenshot, it might help in diagnosing the issue more accurately. But in any case, I recommend reaching out to a professional TV repair service in your area to get a proper assessment and a quote for the repair. They will be able to provide you with a more accurate estimate of the cost involved in fixing your Smart TV.