It's one of the threads that if pulled on hard reveals a lot about early Xtian origins and doctrine. Surprising to many is that some of the earliest forms of Christianity held no salvific importance to the death of the Christ. The various forms of what's called docetic Xtianity, dating from the 1rst century, even held the death to have been an illusion or purely mystical. Their Christ was a teacher and agent of the divine that opened eyes to truths. Clearly, they did not have a ransom doctrine. Even among those who sought to counter these views could not agree on why Christ had to die.
Very early layers seem to include the idea that the physical death of the Christ was almost irrelevant other than capping off the story of the incarnation. The incarnation of God into human form was seen as the saving redeeming act. It elevated human potential to becoming like Christ. He opened the way as it were. To others the death was interpreted as sacrificial in an expiatory fashion yet required beneficiaries act Christlike even to suffer and die to be elevated to Christ's nature. No concept of a monetary ransom from someone. Some seem to have used the term translated "ransom" to mean redeemed. Like the OT passages this implied the standing with God was remedied not that a tit for tat exchange took place. In short, the storyline that Christ descended and was killed, begged for theologians to interpret the how's and whys. Numerous textual alterations are evident today that reveal an active effort to refute one or more of these theological views. Docetism was 'disproven' by repeated references to blood and flesh. If the blood and flesh were essential aspects of the death, then that required more theological theory. I'm tired now, but if anyone wants to break into this I can.