I think I am not doing that, OS, but we'll see as the conversation moves along.
One comment: You said, "...the step before creation, or beginning for our universe..."
I prefer to think of what you are calling "our universe" as "what we humans consider to be the universe." It may not be "our universe" and it may not be "THE universe"...but it surely is what most humans consider to be the universe.
Me...I'm not so sure.
Ok, well let me propose this line of thinking to you. And for the purposes of this conversation consider "part of nature" and our universe as synonymous.
What if something exists that we cannot define in terms of our universe (thus within our knowledge confines,) but it still can cross into our universe with and without being subject to the "laws" of our universe at its will?
In terms of philosophy there are three categories in this discussion I am asking you to consider. What we know, what we do not know, and what we do not even know we do not know. We might decide on the first category in terms of science (systems of process) thus come up with natural laws. We might speculate on the second item and create theory (starting point of systems of science) or belief (conclusion of most religions) that satisfies at least a beginning explanation for the possibilities. Humanity has a long history of doing this, many times over. The third category though creates the most complication in terms of philosophy to talk about. It is just outside of knowledge and even speculation, but potentially can be right on the cusp of discovery.
Your OP argument tries to take what we assume from belief and make it within a confine of explanation from systems of process. For something to be "natural" in our context means the ability to define some basic laws about it.
Your exact OP argument... "As I see it, if there is a god or a creator…it would be a part of nature, albeit a part of nature about which we humans do not currently have knowledge."
That presents some problems about the relationship of universe as we know it to the concept of deity. The former suggests that process where we can categorize it, apply what we know and predict certain things. No matter if we are talking about life or energy, we have something we can apply to it in understanding. The concept of deity though by definition includes another idea we have applied to what we do not understand (i.e., what we do not know but summed up with a system of belief.) In this case, the idea of a supreme being or "supernatural" being. No matter which you choose we are talking about a condition not subject to what we assume of our natural laws.
I am proposing a third option, the ability to cross between our natural laws and the deity position of no longer being subject to them. Perhaps to the point of not being subject to either time or energy as we understand them. But even my speculation means what we do not know, I still cannot speak to what we do not even know we do not know. Nor can you. Which leaves me with the conclusion that you are categorizing a subject from systems of belief into confines of systems of process. To further ask you to explore belief and science, we have no real evidence that "a God or creator" falls into either one.
What if the newer Quantum Science models are accurate and there is no real beginning, the application of infinite time... thus no creator, and nothing to categorize in terms you are trying to?