The ideas you're hashing out sound to me like the ones that have already been analyzed - perhaps poorly - in the debate between Sam Harris, Jordan Peterson, and Bret Weinstein.

In short, is a linguistic error to claim that we should "believe" myth and metaphor.

We shouldn't really asking if myth and metaphor are "true" or if they should be "believed." The right question is, what do we call truths that are conveyed by myths, metaphors, and artistic fictions? The answer is clear: we call them moral lessons. A teenager might watch a film such as Star Wars and learn a lesson about redemption or bravery. That lesson manifests because it resonates in their psyche with an objective truth about human nature and life.

This isn't confusing for most art and mythology because people usually understand which categories those genres of human creativity belong to. That, however, is obviously not true with religion. Seeing authoritative texts as myth and metaphor is simply not the way the majority of religious people read those texts. The can of worms that kind of thinking opens is postmodern: those metaphors are fundamentally subjective because it's not clear at all what objectivity it's conveying without a textual interpretation to view the bible's claims through.

What lessons one extracts from the bible depends crucially on what interpretation one uses to understand it. If someone attaches literal belief to it, that is going to produce very different results than someone who reads the bible in the same way one would watch Star Wars. There is no reason to believe practically anything in the bible actually happened. Now that of course doesn't prevent someone from viewing the bible as a mythology with metaphorical truths similar to a film or piece of artwork that one can extract lessons from. But that does not mean one believes it even in that sense, just as one would never say that one believes in Star Wars.

And even if one does try to see moral reality within images in the bible, that is extremely hard to do if one engages with what is actually in that barbaric text as honestly as is possible (unless one conveniently ignores those nasty sections about god engaging in actions such as genocide and genital mutilation, which is incidentally what many Christians resort to).