GREAT Question, thanks,
The reality is that Jesus did not invent Sacramental Confession [John 20:19-23; 1: Jn. 1: 6-7, 1 Jn. 5:16-27]
Yahweh too used His Priest for the forgiveness of sins; which several NOTABLE differences
There were “just” [if I can use that term] “sins” with no distinction. Certainly they knew in their hearts the seriousness of their actions, BUT all .failure to fully OBEY the LAWS were seen as serious offenses; [Sort of if you break one Commandment you HAVE theologically “broken” all of them by Failing GOD].
And their sins in a literal sense were NOT forgiven by the Priest; BUT merely covered over; which Yahweh then ACCEPTED as they were a people being FORMED [educated] about God and God’s expectations for them at THAT time and place; as God meets all of “where we are” spiritually.
Take unto thee also Aaron thy brother with his sons, from among the children of Israel, that they may minister to me in the priest’ s office: Aaron, Nadab, and Abiu, Eleazar, and Ithamar.
And he shall make good the damage itself which he hath done, and shall add the fifth part besides, delivering it to the priest, who shall pray for him, offering the ram, and it shall be forgiven him.
He shall offer of the flocks a ram without blemish to the priest, according to the measure and estimation of the sin: and the priest shall pray for him, because he did it ignorantly: and it shall be forgiven him,
NOW “Under GRACE” [Romans 6:14], so NT Priest DO have the Power and Authority [Mt 16:18] to FORGIVE SINS [john 17:17-20, John 20:19-23**]
Hope this helps you,