Dear Samsung Member,
Greetings from Samsung Customer Support!
To resolve "Battery drainage" issue kindly follow the given below steps:
1)Battery optimization:-Settings>Select Device Maintenance/Device Care>Optimize>Optimize all options like Battery, Storage and Memory
For more information on battery drainage please click on the link below:
http://www.samsung.com/in/support/skp/faq/1101689
And to resolve "lagging issue" kindly follow the given link: https://www.samsung.com/in/support/mobile-devices/how-to-restart-the-device-when-freezed-or-hanged/
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question) along with video or screen-shots(as provided above). This will help us to further investigate and resolve your concern.
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Thank you for writing to Samsung.
Warm Regards,
Samsung Customer Support