Use APKPure App
Get Screen Off for Root Users old version APK for Android
Shortcut to turn screen off in rooted devices
*** This app requires a rooted device ***
The only function of this app is to turn off the screen.
It can be assigned has a action to some launchers (like Nova, etc) and/or using specific apps.
In order to make it functional, you need to provide root privileges first time that was executed.