I suspect that “allegorical” may not be the best understanding here, but certainly there is much we should not take a journalistic reportage. Brian Brock, in the chapter I> reviewed at PS from Christ and the Created Order, suggests:
Given the peculiarity of the real events, it is clear that Genesis should not be understood to offer a newspaper account… since the conventions of modern positivist historiography assume the stability of the universal causal laws of our contemporary experience as the framing condition of what could conceivably be counted as a true story about the past.
My own instinct is that the story was told in that way because the events were genuinely formational, and that kind of story needed that kind of genre (just as heroic Greek tales needed epic poems rather than matter-of-fact prose). So in that sense, I tend to use the word “mythic” for the genre - but not for the historicity.
We have to remember that there was no genre of history at any time the story could have originated, from 3rd millennium ANE to Babylonian exile. And likewise the distinctions between the spiritual and the physical were very different then from now.
Given that we can’t recover much of the subtlety of those genre considerations, I think we need a degree of flexibility in interpretation. For example, it takes minimall imagination to see that the re-use of the “tree” motif in the OT (eg Ezekiel) and the NT (eg Rev 22) both have to do with dwelling in the presence of God. And since Adam and Eve were, in the story, in the direct presence of God, we won’t be far off if we make the connection.
Likewise the serpent is interpreted in the NT as Satan. But in what “literal” form? Internal temptation? A bad guy? Mike Heiser draws philological parallels to ANE serpent deities to suggest that the serpent was a member of the divine council, legitimately accompanying God in the garden. Now, that gives some interesting grounds for reflection, because it would provide a theological basis for the existence of evil powers based on the narrative itself, rather than some Miltonian concept of a pre-creation angelic Fall.
In other words, the non-literal readings are fine, and even essential, as long as we take their theological meaning seriously.