This 2017 model Sony TV wouldn’t turn on but gave a 6 blink error code. 6 blinks according to the service manual is a backlight problem. Luckily, new strips are relatively cheap. This model uses the style of LEDs that also turn blue. With a new set of backlights, the TV turned on with a picture. With this model, backlight appears can be turned down in the BRIGHTNESS picture mode setting. I would recommend setting to about 50% to prevent future failure.
Info on LED backlight failures here
Info on LEDs turning blue here.