How to play PUBG without lagging in Samsung on nxt?? Give me a solution..!!

Plese tell your experience and performances of Samsung On Nxt after one month from the oreo upadte..!!

Sometimes when I am unlocking my phone using either finger print or power key the brightness level of phone was automatically get into 100%.. After re unlock only it will sort out. But the level shown in mobile same as I set already.

While I am trying to sign in galaxy app it shows ' Samsung account is already exist in account manager'.

What is the use of recent software update that shows October security patch..It consist of 150 mb size..