The Hebraic sacrificial system had nothing to do with pointing to the future.
It was limited in its scope, relating to only minor infringements, mostly unintended or accidental. Some sacrifices did not involve the shedding of blood.
The Day of Atonement, in which the priest lay two hands on the scapegoat - not a confessing sinner's hands - was designed to ensure Yahweh continued to live in the Sanctuary. And that goat which carried the sins from the Sanctuary was not sacrificed but driven off to live with the demons.
As for Paul's opinion and creative imagination, his idea of "salvation" included resurrection and did not stop at Jesus's death. He only states what he believed happened but he never explains how his salvation model operated. For that reason, there has been any number of models.
Augustine's model survived almost 1000 years until Anselm introduced his medieval explanation, soon to be contradicted by Abelard and he by Thomas Aquinas. And so on the explanations keep changing with the times. Luther and Calvin were at murderous loggerheads while the Orthodox Church has its "deification" model.
And running along in the background is Theodicy, which conceivably is a problem created by Monotheism.
What a tangled mess supernatural superstition finds itself in.
Doug