If you forget the password for App Lock on your Xiaomi 12T Pro, there are several general steps you can take to reset the App Lock password:
1. Go to [Settings];
2. Scroll down and tap on [Apps];
3. Tap on [App lock] in the menu;

4. Tap on [Forgot password] at the bottom of the screen;
5. Select [Forgot password];
6. Tap this option to choose different types of identity verification methods, such as Email, Phone number, or Xiaomi Account ID;
7. Follow the on-screen instructions to reset the password.

Note:
Be aware that this method will erase all App Lock data, including the locked apps and their settings.