Samsung just doesn't want to resolve or look into this. Its clearly their mistake which occurs right after an update (and will not able to downgrade to an older version even from service centre). The only solution is to replace the motherboard according samsung.
Never choose samsung again.
Dear Samsung Member,
Greetings from Samsung Customer Support!
We apologize for your inconvenience. To resolve your device hanging issue please visit this link: https://www.samsung.com/in/support/mobile-devices/how-to-restart-the-device-when-freezed-or-hanged/
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