What is the black screen when the phone is unlocked?

Most likely, the starter was uninstalled.

Basically, it can be confirmed that your mobile phone uninstalled the launcher after root. If it is uninstalled, it will be useless to restore the factory settings. If it is not restored, you can install a desktop for your mobile phone directly on the computer with pea pods and other assistants, or turn on Bluetooth in the notification bar, and just send you a desktop with a previously paired mobile phone.

If the factory settings are restored, USB debugging cannot be turned on, so the method just mentioned cannot be used. Try sending a text message to this phone from another phone. You can see this short message in the notification bar of any website, and click Enter to enter the browser. You can download a desktop from other websites, which requires a data connection in the notification bar of the mobile phone, and the mobile phone has its own browser. If you restore the factory settings, you should only try the browser that came with your system.

Remember not to make mistakes in the future and immediately restore the factory settings.