The essay offers a critical reading of Karen Barad's and Heinrich Päs' philosophical interpretations of quantum mechanics, using a perspective on science and religion called Categorial Differentiation approach which is largely inspired by Wittgenstein and van Fraassen. Barad and Päs are ontological realists, but their philosophies of quantum mechanics depart, in different ways, from what I call scientistic realist interpretations of quantum mechanics, which are typical for the analytic philosophy of physics. After an overview of the ontological turn in the philosophy of quantum mechanics and explaining the basic difference between scientistic and existential kinds of realism, I examine central features of Barad's agential realism and Päs' quantum monism. The Categorial Differentiation approach, which is a normative perspective on the relationship between science and religion is introduced, and its relevance for the philosophy (and theology) of quantum mechanics explained. I conclude the essay with a critical but appreciative analysis of Barad's and Päs' interpretations, including their ambitious existential and moral visions, focusing on the ways in which they relate the science of quantum physics with what I call 'religion' in this essay.