1. Turn off fast charging from device care
2. Discharge your device completely 0% and charge again 100% with slow charging speed.
3. Perform a wipe cache partition by going to recovery mode.
It will fix the battery draining issue along with slow charging problems facing other users. It'll definitely help you.
Check this video.
Dear Samsung Member,
Greetings from Samsung Customer Support!
To resolve your device battery drain issue please visit this link: https://www.samsung.com/in/support/mobile-devices/samsung-mobile-battery-drain-issue/
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
Thank you for writing to Samsung.
Samsung Customer Support