It is generally not a good idea to conflate IQ with knowledge of spiritual truths, but certainly if someone believes thos or doesn’t believe it, how they got to their conclusion is partly determined by their IQ I expect.
I note, and this is not based on any set of experiments or peer reviewed studies that I know of, much though they would be worth doing, that people around about the average IQ tend to flock to mainstream views while being convinced that they put the thought into arriving at their views. They also tend to think that those who disagree are stupid.
Those with non-mainstream views contain an overrepresentation both of those whose IQ is well over the average 100 and those well below. The way they hold their views (how nuanced they are and how truly original) and how they arrived there is the main determinant for whether we are dealing with a potential genius, a textbook imbecile or anything in between, including the occasional person bang on average but who got lucky/unlucky/blessed/cursed in his friendship circles.