Ok guys I have managed to come up to solve both Battery Drain and Heat up issue, I hope this helps everyone who are having the problem and it's for all iPhones with iOS 13.5.1, follow these steps until iOS 13.6 is release with next week or so:
Battery Drain Issue:
1. Switch to light mode always, turn off Dark mode.
2. Turn off background app refresh for all apps.
3. Turn off location, only activate when you need it for the app.
4. Turn of all Synchronization of iCloud and your Backup to iCloud.
5. Turn of Siri all options.
6. Close all background apps after using it.
Heating issue:
1. Turn on light mode always, turn of Dark mode.
2. When watching video, lower the volume to 50% and then listen.
3. Don't use Camera for very long time and use minimum settings for it.
4. When playing games, lower the volume and use it for less time.
5. Use low power mode when using heavy apps.
Good luck People!