I often leave Steam running in the background. Indeed, KDE seems to be suspending more reliably after I exit Steam. Thanks for the suggestion!

Looks like that script is for Gnome (based on the StackOverflow post listed on the project page, it talks to org.gnome.SessionManager via dbus). I wonder if there is a similar way to talk to PowerDevil?

Yes, “sane” service is already in the “Allowed” list.

Added “mdns” service to allowed list for public zone, still get the SANE error. (Previously added 5353 UDP per another suggestion – sounds like this is the port for mDNS)