Maybe we can't rule out a 'powerful, intelligent creative entity' – but why would you even think of that?

Others have thought of it. I'm asking why I ought to dismiss it. I think we have good reasons to dismiss, for instance, Christianity, because of the positive claims it makes. I don't see the same contradiction with something like deism.

And of course it just shifts the question to the next level, because where would that entity come from?

This isn't a compelling argument to me. Can we rule out an intelligent prime mover with what we know about the universe? If so, what do we call the events that first caused everything to be?