Okey, I will list some, you can check it by yourself:
✪ The habit of using the device in the wrong way
★ S8 Plus is equipped with a powerful configuration and many trendy features. This makes you experience the machine with high intensity continuously and overload it.
★ You open a new application without completely shutting down the old application. You leave many applications running in the background, using many features at the same time.
★ You charge the device with a low-quality or non-genuine charger. At that time, the device often lagged during charging.
✪ S8 Plus has a software error
★ Memory is full, RAM is consumed by too many applications installed and lots of data being downloaded.
★ The Android version of S8 Plus is old but has not been updated yet.
★ The device's software has been conflicted due to corrupted rerun process or due to an incompatible application on the device, etc.
✪ S8 Plus has a hardware error
★ S8 Plus is dropped, bumped or subjected to similar forces.
★ Meanwhile, the screen, main and components will be at high risk of being damaged and causing extremely annoying lag.
That's all, you can check it. If you can not find the reasons, maybe it starts from the developer instead of your device got problems, you can send your problems to the developer of PUBG