Please follow the below mentioned steps in order to resolve the issue:-
1) Adjust the brightness of the device then check (Setting > Display > Brightness).
2) Run the device in Safe mode and check the issue.
3) If issue still persists, create data backup and reset the device.
4) Check the software update via FOTA or Smart switch PC Suite.
For further assistance, register your concern in Samsung members app (Open Samsung members app > click on “+“icon > send feedback > Error report/Ask Questions).
Team Samsung Members