Another aspect of "God" arises from the idea of "isness", that I mentioned on 17th December 2016: the bare revelation that something exists, as a revelation in its own right. Matthew Fox in his book "original blessing" attributes the word isness to Meister Eckhart (as "Istigkeit") - but I've been unable to find it in Eckhart's Works!
Anyway, it's a great idea: Isness makes the difference between on the one hand merely noting that an object is a tree (and so what?) and on the other hand encountering, connecting, with the reality and presence of this being that is before you as a tree.
But, common! - "God" isn't an abstract theory: it's an idea that has shaped Judaism, Islam and Christianity and has over centuries raised up fighting between them. Implicitly or explicitly,"God" is the first word of the texts by which these religions live: Hebrew: beresheet bara elohim (in the beginning god created...); Islam: bismil lahir rahmanir rahim (in the name of God, the Most Gracious, the most Merciful); Christianity: en arche en ho logos (in the beginning was the word).
The mystery of pure being spans from the opening of the cosmos to the climbing of a caterpillar.