Supernatural isn't a useful concept

[Ignorant]

This, to me, sounds like a "I can say 2 + 2 = 5, therefore it's true (even though I don't know how)" kind of logic.

Without clear examples and elaborations, I have no idea what else to say in response to this.

I'm sorry I wasn't much help.

Your question seems so revolve around the idea of a changeless act causing change. Like I said, anyone who pretends to know exactly what that means and how it operates is not being genuine, or else they are ignorant of a few things. That does not make the idea illogical. You might call it a "natural mystery". Not a mystery in the sense that we can't say anything about it, but a mystery in the sense that we could never possibly say everything about it. So let me say one more thing =)

Suppose three changing things exist. Each of them may only continue in their changing existence as long as they participate/share in the unchanging-pure-act-of-"being"-subsisting-as-itself (see arguments from contingency for necessity). But if EACH of the changing things participate in the ONE unchanging-pure-act-of-"being"-subsisting-as-itself, then ALL of these changing things exist in parallel with a single unchanging thing.

Pure-act-of-"being"-subsisting-as-itself is not just "another thing" in our cosmos. It is "thing-ness" itself. It "is" in a radically different way than anything else. <= Those claims are a posteriori conclusions derived from observing the things in our cosmos. They are not a priori assertions. So you are free to disagree with those conclusions, but if you grant them for the sake of argument, you also grant the premises that led to them. If you do that, then there is no contradiction, even if the reality they describe does not have a readily useful analogy or image.