If the problem persists, you could attempt performing a factory or master reset as a final option. It's possible that the latest version contains problems that resulted in terminal errors that can only be fixed by wiping your device. However, this will result in data loss, so make sure to back up your crucial files. Because your iPhone may not respond to touches, you'll need to use iTunes on a computer to do a master reset. You'll need a Windows PC or a Mac machine with the newest iTunes software installed and operating on a later or newer OS version. Here's how to restore your iPhone 7 to factory defaults using iTunes, in case you need it:

1. On your PC, launch iTunes.
2. Use the USB or Lightning cord that came with your iPhone to connect it to your computer.
3. Enter your device passcode or touch the choice if asked. to Trust, This Computer on your phone then follows the onscreen instructions.
4. When your iPhone appears in iTunes, choose it. If it doesn't appear in iTunes, restart both your iPhone and your computer.
5. On the iTunes main screen, go to the Summary panel.
6. Restore [iPhone name] by pressing the [iPhone name] button.
7. To confirm, click Restore once more. This will cause iTunes to begin wiping your device and installing the most recent iOS version.
8. Your iPhone will reboot automatically when it has been restored to factory settings. You may set it up as new when it has done booting up.