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.