And it is said that Keter is the Malkuth of the Limitless Light, which has some credence. Also, there is a theory that our own "Malkuth," the physical universe, began by a singularity originating in a
different physical universe. In such analyses I think a model of the Tree based on the
Rhizome (a theoretical maze in which every junction and path are connected to all others) would be more useful (although perhaps not stricly Kabbalistic, as that model assumes multiple entry points). As Umberto Eco discusses in one of his books, the Tree of Life is essentially a Mannerist maze, but its ideas are a Rhizome, so up or down, left or right are merely human constructs that aid in understanding.
I sometimes amaze even myself at how pretentious I can be
