Thanks for the information. I'm running KDE Neon on a virtual machine, downloaded from <https://neon.kde.org>, and I can tell you that there's no 'org.freedesktop.PowerManagement' or 'org.kde.Solid.PowerManagement', that's why I'm a bit puzzled.
> FWIW, I would always call login1. In fact, I would always call everything, worst case you inhibit on multiple fronts, but given 1 inhibition is equal to N inhibitions it makes no difference. Trying to figure out which of the 5 gazillion interfaces to call is nothing but a source of tears. Lol, yeah I peeked in the code of caffeine-ng, and indeed that's what the author does, he just inhibits with every way possible at the same time. I find it a bit crude, but I guess he found out it works best like that. Cheers :)