Just as Hashem is above Time Matter and Space then so too the Chelek Eloka Mimaal / Godly particle / Godliness or whatever you would like to call it is above time matter and space. That being the case the question this post started with falls away and doesn’t start.
Hashem’s Oneness as explained in Shaar Hayichud of Chovos Halevovos has more to do with Unique / Unequalled / Unlike any other and means a lot more than just the numerical value of one which is obviously the case but largely irrelevant to something that is above time matter and space.
The question posed here that the idea of Chelek Eloka Mimaal implies a “splitting” of Hashem is simply an ignorant and foolish attempt to force physical dimensions on something which is not physical.
This discussion has nothing to do with Lubavitch or Kabbala, this discussion is simply the result of enormous ignorance about what Hashem’s Oneness means.
Tiawd, Learn Shaar Hayichud before you attack / attempt to cross out explicit words of a great sage like the Baal Hatanya.