After years of study, this is about the only consistent and coherent Christian Theology I can extrapolate:
God is goodness.
Grace (charis) is God’s active presence in the world; God’s persuasion toward us.
Faith (pistis) is our draw to the good; our persuasion toward God.
Belief (pistis) is acting on faith.
Atonement is the experience of doing the good.
Salvation is the transforming effect of the experience of doing the good; our sacramental encounters with God.
Sanctification is the process of becoming in participating with the good.
Theosis is the eschatological end.
This makes coherent use of the terms as near as I can tell to their first century CE usage, except perhaps for “atonement” (but as I describe it, I am faithful to its original English usage, which was not הַכַּפֹּֽרֶת ha-kappōreṯ).
Note too, the above describes universal salvation through participation, which is a very old, Jewish idea; a consistent theological thread in their thinking.
For humanity, Jesus is exemplar; what humanity is like, and what God like. However he rectified things in his life and death aside from that, no one knows and we’re silly to dig in anchors of absoluteness, or salvific contingencies on getting that mystery intellectually correct.