Egyptian religion had no scripture, no creed, and no word that maps neatly onto "religion". What it had instead was maat (a term covering order, truth, justice and the correct arrangement of things), understood as established at the first moment of creation and under permanent pressure from isfet, disorder. Almost everything the state did in a religious register was framed as maintaining maat rather than as spreading a teaching.
The gods were numerous, local, and unstable in outline. They merged, split and absorbed one another: Ra of Heliopolis combined with Amun of Thebes as Amun-Ra without either ceasing to exist separately, and Osiris, Ptah and Sokar fused into a funerary composite. A god had a home city, a temple, a household and a cult image, and the daily service of that image was the core of temple religion. The statue was woken, washed, dressed, fed, and shut away again.
Ordinary Egyptians did not attend. Temples were staffed by rotating priesthoods and closed to the public, and lay contact with the great gods came mainly at festivals, when images were carried out in procession and could be put questions, with the answer read from the movement of the bearers.
The king appears in every temple relief as the officiant, whatever priest was actually doing the work. He was the point at which human action and divine order met, associated with Horus while living and with Osiris once dead. That is a statement about an office, and about how the state described itself. It is not evidence for what any individual Egyptian thought about the man holding it.