I have been working with i3 for a while on Ubuntu 18.04. Controlling some of the peripherals has been quite elusive, since the system settings application shows only a few of the settings available in Unity:
The i3 folk claim that this has nothing to do with the DE, but is rather an issue with my system. What do I need to do to have the same settings controls in i3 as I have in Unity?
You should try to declare environment variable with GNOME desktop and launch GNOME Control Center with it: