Are there any books (Either fiction or nonfiction) that explore the mythology of deities in religion?

Hi everyone

I'm looking for books that cover the supernatural side to modern day religion

Maybe a fiction about how Jesus returns to an exoplanet (A la Left Behind?)

Maybe a book about Greek gods and how they're so sad no one worships them anymore

Maybe aliens that become gods because of technology

I just want something that hasn't been covered already by what we know already about modern day religious gods and deities

Anything like that exist already?