This article made me smile for a number of reasons, including your careful attempt to describe what cannot be described.

If we start with something and then remove it, then what do we have? Something? Nothing?

If we enquire into what we are, closer than the physical body, all of our ideas and beliefs, thoughts, etc., and remove everything that we are not then what do we come to other than nothing? If we consider the physical world which appears to be material and substantive but we look close enough at it then we discover cells, molecules, atoms, and smaller particles until there is nothing. Thus, can we say that nothing exists and/or can we say that everything is nothing at its essence?

You wrote: “Thus, reflecting on the possibility of nothingness brings us, in short, to theism, to the positing of a supernatural source of natural things, a source we generally call “God.”

God is not nothing; it is an idea and it moves, acts, thinks, creates, and destroys. Essentially, it is consciousness personified, which is something, not nothing.

You did touch on something that is important, which is the way we perceive things. We have been conditioned, trained, to see the world in a certain way, and this comes from the ideas of people who have taught us who we are and what the world is. But it is a problematic perspective that relies on preconceived ideas of reality. Why do we struggle with what nothing is, or whether there can really be nothing? Is it because we have been conditioned to believe that nothingness is not possible?

For those like myself, who have taken years to observe the essence of life, including what I am, at the core is an ineffable reality that may be called nothing, and out of this nothing comes into existence all that we say exists, including consciousness and all ideas and thoughts, including God. A better word, however, may be capacity instead of nothingness. This is a word that the philosopher Douglas Harding used. Thus, I seem to be the capacity for all that exists. The Cambridge Dictionary notes that capacity refers to the total amount that can be contained or produced. So, within me is the capacity for all else — but this “me” is not the self of the ego, the body, or thoughts. Rather, it is the ineffable out of which such things seem to arise.