Thanks for being with Samsung and sharing your concern. We would like to inform you that kindly follow the steps below to resolve the issue :-
1 Adjust the brightness of the device then check it (Setting-->Display-->Brightness) 2 "Disable the " Show Screen Updates" option in developer options or completely disable the Developer options."((Setting-->Developer options(If its available & highlighted)-->Show Screen Updates)) 3 Check third party application if downloaded recently, Post which issue occurred. Then, check in Safe Mode. 4 If in Safe mode problem is still existing we advise you to create the Data back up & Factory Reset the device. "5 Periodic Software Update through FOTA , SMART SWITCH or Smart Tool is intended to improve the battery life as well. Be sure to hit ♡ when you find an answer that works for you. "