Don't know why phone is getting restarted automatically after updating it. Could samsung support team fix it it's annoying it's restarting frequently unable to work
One of the issues faced certain users post update. Waiting for a resolving update is the only option, which might take a while. Or you can downgrade to 11.
Many of user face this issue in different model the main couse of thi issue file corruption . So update ur software one shot through strong fast wifi network only
We acknowledge your query and apologize for the same. We request that you kindly visit the service center for a physical inspection of your device. You can locate your nearest service center with this given link: https://www.samsung.com/in/support/service-center/
