Theological Disputes :
Why only one Creator? Why can't the universe be the collective creation of the divine collective?

Yyy: Probably because where there are two or more, there is no secret. And this contradicts the definition of God as being incomprehensible (incomprehensible = secret).

That depends on who it is incomprehensible to. For humans and the divine collective can be incomprehensible.

zzz: in principle, only at different stages of creation.
as there is the chief architect, other architects, engineers, builders, malars, diversity workers...

ddd: the divine gastarbytes