Where does that assertion come from anyway? "symbolism isn't spiitual". I guess you mean that the symbolism in "Alien Covenant" is not spiritual. Well, I guess in that case you are correct, the film's symbolism does not intend to convey a spiritual truth as such, even though Scott has tip toed around the theme of "faith". It just uses religious symbolism to evoke an alternate version of the human genesis, its search of answers and ultimate fate. In any case, the biblical references channeled through "Paradise Lost" have a premonitory value, which is suggested by the story's recasting of several characters from the Bible as synthetics, futuristic tycoons, hapless science officers, etc. There is a deliberate intention to be "blasphemous", and rightfully so. Some of the best sci-fi is like that. I would recommend an anthology called "Dangerous Visions" where you get plenty of this type of edgy sci-fi.