John 20 doesn't teach that anyone was a “proto-church.” Again, that is isogesis from your teachings and traditions.
And NO, not “all of us” are children of God. The “New Birth,” “Regeneration” is necessary to become a child of God. If “we all are” children of God, then nothing in the Bible means anything at all. There is a great Biblical distinction between those who are children of God and those who are not. And there are children of DARKNESS. And there are children of the DEVIL. NO, not “all” are children of God.
However, whatever you belief about the nature of the Church, what makes you think you are not in need of a confession and absolution?
not all of us are children of God.
Again, whatever your beliefs are, what makes you think you are not in need of a confession of sins?