I think I found what you’re looking for. Check out this post: https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=18200
basically, edit /etc/kbd/config
and set
BLANK_TIME=0
POWERDOWN_TIME=0
then reboot or /etc/init.d/kbd restart
I’m at work right now, so I haven’t tested this yet. I’ll do some preliminary testing tonight. I don’t think that it’s a good idea to make this a default change, but, perhaps set it during dietpi-software installs then reset it before the reboots…