Quoting Rob Owens (robowens13@???):

> I haven't tested on Devuan but on my Funtoo system, LightDM does not work
> unless dbus is started. Note that this is not a package dependency issue.
> Dbus is installed, but if it is not running prior to starting LightDM,
> LightDM will give me a black screen with a blinking cursor.

Well, that's unfortunate, but there is a large set of choices of X
Display Managers, including ones that greatly predate dbus. (I
personally think xdm is just fine, though I'm aware this view isn't
widely held any more.)