Not necessarily true - an infinite god would not "need" other beings, higher-dimensional or otherwise - to intercede.

The cool part is that it is not necessarily false either - if a plethora of beings were created, like not just animals & plants or even bacteria and fungi and viruses, but also beyond matter-based ones into gaseous forms, plasma, raw energy, or other stuff we don't even so much know about (involving patterns of those raw things but connected in ways that we cannot yet see and likely have not began to fathom), well... they could be put to use in an intercessory capacity.

And if so, then perhaps we too will do similarly, when we grow up enough - e.g. if we create AI and become a "creator" to them. They too will have a purpose or at least reason that they were created, and they, being like us, will likely want to know what that is. Perhaps we will hard-code those answers into their cortexes, or perhaps we won't bother to explain at all, but likely we would do something in-between. Just like the stories of the various gods that we have heard about all around the world explain might have been done to us. Who really knows? Certainly not I, but it is fascinating to think about.