Alain, you ask for thoughts. One of the problems with the question of "the Ransom" is that a logical assessment, ie one which cannot be disproved, is not possible. Any doctrinal proposition which could well satisfy religious minds and hearts is not compatible with evidential, analytical reasoning.
The religious mind is very biddable and prone to selecting his or her favoured viewpoint. Facts don't come into it.
The very nature of all religious belief is that it has at its focus an invisible being for which concrete evidence cannot be found. Because of the lack of evidence, religious belief is an infinitely flexible stream of ideas. An ironic consequence of which is pride in the certainty of "rightness" of conflicting sectarian doctrines. None of which is useful in the foundational understanding of anything, except perhaps this: that there has been a time honored superstition in the human psyche for humans to yield and sacrifice to an unknowable spirit power.
Belief in gods from prehistory forward must have led to a sense of obligation which required appeasement, this involved killing animals. Human death as a propitiatory sacrifice (atoning, reconciling) would have been seen therefore as the most potent of all sacrifices. A fact the Bible used to argue that a creator sky god had killed his son for us.
An idea hard to swallow in the post-christian twenty first century.