After updating my S21FE to UI 7 4days ago, my phone was working fine , no issue found . Today afternoon the green line starts appearing on my seen. 

Samsung galaxy mobiles are the best mobile,why because it contains many advanced features and you can use your mobile in easy way,better camera excellent screen quality, better battery and comes to design it looks premium,To be honest  Samsung mobile...

Captured with Galaxy C7 pro

I'm using c7 pro mobile when switch on flash it was not working no response of light.. please check the problem as soon as possible...

After updating my c7 pro to nougat .... it starts video lags in all apps ...