Pressing the keyboard screen only flashes, and the typing box disappears as soon as it flashes. I can't type or even send messages. I tried again, but it still didn't work.

Hello, please back up your data, enter recovery to clear all data (shut down, press and hold the volume up+power on button to enter recovery), and do not install third-party system security software for the time being to see if it can be restored to normal.

Thank you for your support and wish you a happy life!