I'd recommend Michel Faber's The Book of Strange New Things (2015).
Anything by Shusaku Endo: my favorites are The River and The Holy Fool. Of course, you'll already know about Silence. And anything by Dostoyevsky.
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I recommend British author Susan Howatch. It’s been many years, but I remember the impact of her Starbridge series (6 novels). They explore religion with an approach that is both frankly spiritual and highly intelligent. I haven’t encountered anything else like them, before or since. I just learned she also wrote a St. Benet’s series of 3 books; I don’t know anything about those, but I’m looking forward to finding out.
Kim is the best novel about Buddhism ever. It is also about a million other things, but it captures some essance of a deep beautiful being in the person of the lama and his love for Kim's future awakening.
Here are a couple more: The Chess Garden, by Brooks Hansen, and The Hummingbird's Daughter, by Luis Alberto Urrea. For me, these evoked the ineffable.
Another beautiful, thoughtful epistolary novel that deals with faith, doubt, and love is Carlene Bauer's Frances and Bernard.
A Canticle For Leibowitz would be a good addition to this list.
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One of the most moving books I've ever read is Death Comes for the Archbishop by Willa Cather.
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How about "The Cardinal" by Henry Morton Robinson?
I would recommend the novels and short stories of J.F. Powers who wrote movingly about Catholicism. In particular the novels "Wheat That Springeth Green" and "Morte D'Urban"
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Lovingly and hilariously. Powers really knew the Midwest and both celebrated and slyly poked at the region in his novels and stories, particularly in “Morte D’Urban.”
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You might be interested in Gail Godwin's fiction.
Didn't care for End of the Affair, although I will say that it's beautifully written. Ceremony and Temple of the Golden Pavilion are great suggestions, as is Gilead. On the religious end, I'd throw in Silence by Endo, or for some religious non-fiction and more C.S. Lewis with A Grief Observed, which is about death, but still includes religion in a phenomenally exquisite fashion. (I'm an atheist.)
I’m remembering back some years to the wonderful novels of Chaim Potok, particularly “The Chosen.” Two teenage Jewish boys, one modern orthodox, the other a genius who is the heir to his father’s Hasidic dynasty, but longs for intellectual and personal freedom. A lovely, compassionate story with a lot of interesting insights into Judaism.
5
Shikasta, by Doris Lessing, for the exploration of “substance of we” feeling (akin to radical inter-dependence).
Don't forget British Catholic author David Lodge, whose characters (to a greater or lesser degree) deal with or at least recall the struggle for faith in the sophisticated secular world.
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I would also recommend The Sparrow and its sequel, Children of God by Mary Doria Russell - stories of a Jesuit priest who is sent on a mission to a newly discovered planet. Religion/ science fiction
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I was just about to recommend those myself.
And, I will add Guy Gavriel Kay's stunning The Lions of Al Rassan which takes place in a fictionalized Moorish Spain which aptly probes the conflicts of culture and religion in that arena.
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Lot of bad science in The Sparrow, though, and ignorance (? willful) of the historical response of the Catholic Church to priests and nuns who have been raped and debased in war.