Sorry, Christ alone makes atonement for sins, and in the Old testament it was faith upon the type of sacrifice made by Abraham regarding the Lord "thou hast not spared thy only begotten son".
Is that not your understanding??
Therefore, it is right to reject the book of Sirach for this severe error.
The book of Sirach was inspired by the Holy Spirit. Are you saying you know better than the Holy Sprit?
Every sin destroys, obscures, or denies what is good; God, however, is all-good and the author of all good. Therefore every sin goes against God (also) and must be set right again through contact with him.
Already in the Old Testament God says through the prophet Ezekiel: “I have no pleasure in the death of the wicked, but that the wicked turn from his way and live” (Ezek 33:11). Jesus is sent “to the lost sheep of the house of Israel” (Mt 15:24), and he knows that “Those who are well have no need of a physician, but those who are sick” (Mt 9:12). Therefore he eats with tax collectors and sinners, and then toward the end of his earthly life he even interprets his death as an initiative of God’s merciful love: “This is my blood of the covenant, which is poured out for many for the forgiveness of sins”