My first thought was an electronic control card controlling all LEDs should be bad.
Came to AppliancesPartsPros.com and found comments on symptoms like "no lights" or 'lights failing to turn on" therefore videos recommending door switch replacement.
Then found a video showing the location and replacement of the LED card in the main light at the refrigerator side ceiling. Also noted a comment by a customer about 'lights flickering"; that was our case!
As shown in the repair video, with careful pressing in the 2 front tabs with a small flat screwdriver, the swapping of the little card which included on board the LED lights in the main location, took barely 10 minutes and the lights where back steady. Upon inspecting the old card with a magnifier, could see all welds at the pins of the LEDs fried; probably a power failure and subsequent power back with some small surge, was enough to take the little card down!
Have purchased parts from APP for many years, they never fail and advise wisely on your most probable culprit; then with great professionalism takes us via "cyber-way" to our solution.