In my view both sides are dismissive of the obvious. The Logos concept was an entirely Greek concept representing the bridging of Heavenly and earthly worlds, immaterial, and realities. Philo and others merged this with OT depictions of deity to explain how his God could be both transcendent and relatable. The earliest Christians would never have denied this provenance. Many thought of the Greek sages as having shared in divine revelation, not as enemies of it. Was this Logos (or Great Angel, created creator, Son of God, image of God etc.) merely metaphor? It depends upon your definition; we are after all discussing imagery of invisible spiritual concepts. Where does metaphor start and end? Conceiving a spirit being acting as agency of The transcendent God,IMO, meant more than just metaphor but not tangibly other than that God..... a piece of God? The Holy Spirit in many ways mirrors this as yet another emanation of The God. .
This 'Mystery' was lost on most Christians of later generations. The Gospel tales were too successful, the allegory became the reality. The Trinity became a compromise, Mystery literalized.