I set 2 Kali non-Purple machines for:

Settings, Power, Display all set to Never when plugged in.

Machine is VM and so Battery and Hibernate all set to none.

The Kali non-Purple machines stay ON 24 hours a day.

I set Kali Purple the same way and after 2 or 3 minutes the screen reverts to login.

I do not know how to fix this.

Thank you.