Many possible causes... All of them bad I'm afraid.
It could need a skilled technician to open it up and swap out a motherboard, IF a replacement can be found.
Or it could be a dirty ribbon connector that needs to be pulled and cleaned and reseated PROPERLY.
Or it could be a failing display module. Again, replacements may be difficult to find.
I have no way of knowing your skill level with repairing electronics so I leave it to you to explore any DIY or paid service options.
Gary