Turn off Selfie face correction option from camera settings to improve front camera selfies and pictures. It will get rid of overexposure,over processed and weird beauty mode from front camera.You can find the option in Camera settings - Save options...

The lag is finally fixed with the 0.14 pubg update. Now it doesn't lag after every 3-4 second and while moving. It took 5 months for pubg to optimize their game for s10.