Creator is less about pure potency and more a capacity to do a particularly impressive thing, but not other impressive things. Almighty or perfect would entail such a thing that could have no equal or share any power, which would arguably support Unitarian theology.
Conception of something as the most powerful doesn't make it so, nor does it necessarily follow to them being something that must exist from that. I could conceive of something nightmarishly scary, but it doesn't come to being because of that. This isn't that one horror movie.