Dear Samsung Member,
Greetings from Samsung Customer Support!
Please be assured and to resolve "Device lagging" issue please follow below given steps:
1) Check device in safe mode: Press and hold the Power key, when Power off icon appears >Press and hold the power off icon.
Exit safe mode: Hold the power button and select restart on the device.
2) Reset the device: settings >General Management > Tap on Reset.
Note: Before reset make sure to have back up of the data via Smart Switch Mobile App
(Install Smart Switch App > Open > Click on Memory Card Icon >Back Up option > Choose the data for Back up > Back Up).
Please visit this mentioned link to resolve your device lagging issue: https://www.samsung.com/in/support/mobile-devices/how-to-restart-the-device-when-freezed-or-hanged/
To resolve "battery drainage" kindly follow the given below steps :
For heating issue--Follow the link for more details :- https://www.samsung.com/in/support/mobile-devices/why-the-heating-issue-occurs-in-mobile-device/
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question).
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Thank you for writing to Samsung.
Samsung Customer Support