Books with characters that persist in their traditions despite a crisis (or lack) of faith?

I’m looking for stories like San Manuel Bueno, mártir, or HBO’s The Young Pope, in which a character continues to operate within their (preferably cultural and/or religious) tradition despite losing faith in it. This lack/crisis of faith need not be explicit, I’m okay with it being ambiguous or implied.

Preferably this character would be the protagonist, but a story with any prominent character fitting these themes would interest me.

Final qualification: I’m more looking for characters that continue to operate within their tradition out of an altruistic or even conflicted motive, not for personal gain and/or selfish reasons. Thanks in advance!