It wouldn't be a religion based upon physical rituals, or one based upon emotional devotation like xtian monks, it would be intellectually based... full of theories and ideas, and very complex. Such religions already exist. They would have all kinds of theories about the workings of spiritual realms and probably how to advance too.
Of course even if people are not only geniuses but wise, and well knowing... all that's needed is for an Eternal to prove themselves to a people and if their philosophies agree, the civilization may worship the Eternal
answer
Of course even if people are not only geniuses but wise, and well knowing... all that's needed is for an Eternal to prove themselves to a people and if their philosophies agree, the civilization may worship the Eternal
-Iniach