The gospel is glorification by faith. Forgiveness was granted in the beforetime, but not glory. Everything awaits the fulfillment of the Adamic covenant. Jesus comes to the place Adam did not come to, and in Him so do we. We receive forgiveness and glorification in Him, in cross and resurrection. I can certainly accept “preliminary righteousness” for Adam and “perfect (in the Bible sense of mature) righteousness” in the resurrected Jesus. I receive the latter, by faith. The believer, as you say, is “perfectly and eternally righteous,” because he is “in Christ” and that is what Jesus Christ is.

In the Supper we receive childish bread, the food of priests, breakfast; but unlike under the Old Covenant, we no longer pour out the adult wine of kingship and of evening rest, but drink it also. All, from alpha to omega, is given us. Bread - birth - Tree of Life and also Wine - death - Tree of Death (of K of G & E) are given us.