You’ve been reading too much Parmenides or Plotinus.
When I was a kid in Texas I found myself staring at a fence, and realizing, though I didn't have words for it at the time, that the verb 'to be' is the fundamental misapprehension underlying the entire illusion. By 'illusion' I don't mean a bad thing ... it is what it is ... but it is an illusion. And that's not say I understand and have mastered the illusion - I live and behave as if it's real all day long, I just don't treat it as if it's really real.
But I have intruded, I'm not here to say questions of the nature of dimensions don't matter ... although in the context of the bigger question, it's totally irrelevant, a symptom of the misunderstanding. The origin of the universe is mind. The question is, what is mind? It could be said that it's the 'container of the dimensions' ... if you had to say anything at all. But it's not the other way around. Mind contains dimensions, the mind does not exist within the dimensions.