It seems that the recent software update broke all M31 devices. As of now there is no official statement from Samsung regarding what should be done.
You people can't go the the service centre due to the ongoing lockdown.
People who have a computer or laptop can fix the issue for time being by rolling back to a previous version of the software.
Just visit this Sammobile page and download the Firmware for February
Download the firmware and install it on your smartphone using ODIN, Instructions are available on the Right hand side of the page itself.
Hope this helps you until Samsung provides a fix for this issue.