You might want to present the in-story text as a parable which means the story has a teachable message, rather than words like "mythology" or "religion" which imply a spiritual calling.
the role of the text in context, and the protagonist's reaction to it
are the important points
The protagonist needs to relate to the story. He identifies with that situation, and has a realization about an earlier experience, something he failed at. It might be the wrong realization or he might identify with it for the wrong reason, but to him this story makes a kind of personal sense when other myths were just a wall of text.
In every culture there are the "big religion" stories about sacrifice and the gods' transformation to deity, but there will also be hundreds of smaller parables that are just there to show how the god was inherently wise, or honest, or a trixter long before they reached their final status.
A very silly American myth that I was told as a child (even in school) was that George Washington "could not tell a lie". He receives a (magical?) hatchet made of silver and uses it to chop down his father's favorite cherry tree. Confronted by his father, Young George fesses up to his over-exuberant tree chopping – or whatever, the story is ridiculous. Worse this parable has nothing whatsoever to do with the themes of founding a nation, creating a representational democracy, being a general who leads a revolution – all the things George Washington is actually famous for. It's just a parable about why kids shouldn't lie, and giving quasi-supernatural abilities (being unable to lie) to an historical figure.
Modern biographers would view the parable as a cultural artifact, but not believe it actually happened. As a 1st-grader this parable was mixed-in with history lessons which were presented as "facts". I absorbed it without question, and never considered it seriously until I was an adult and found it hilarious – mythology bordering on propaganda.
Your protagonist might relate to one of these smaller parables, and miss the deeper religious themes. He might walk away from the parable focusing on the wrong message – something like misinterpreting the George Washington story to mean that little boys can commit vandalism without consequences as long as they admit to it afterwards, or somewhere there is a magical truth ax once owned by George Washington.
The temple acolytes could even "lampshade" that this particular story is not necessarily a core philosophy, but still be glad something has sunk in.