Hey frnds... In my Galaxy m51 there came an issue since 4 days from now .. I am not getting my new messages in my fb messenger app when I open it then only it notify... I also did off the adaptive battery optimisation option but still it ...

When i touch my screen or slide it then is keep flickering plzz solve this...help me 

How fix it plz help me    Plzz see this video

While running any apps but sometimes its closed automatically and even there is lag while typing any msg...

Today i have updated my Samsung galaxy M51 phone but I didnt get Secure folder on it and except it i got the new features..How to fix this issue