According to your hermeneutics, that is inference on your part for the sake of your theology, for it does not state "God is three in one."
So much for being literal. . .I'm as "literal" as you are.
I don't say "God is three in one". I say God is One - Father, Son and Spirit for the Father and Son are One and the Holy Spirit is the Spirit of God
The reason I say this is Scripture states God is One.
Scripture states that the Holy Spirit is the Spirit of God. And Scripture states that the Father and Son are One.
Just saying "Three in One" is more of a slogan than a doctrine.
Essential doctrines need to be in the text of Scripture. Secondary teachings not so much. The Atonement is an essential doctrine because so much is built upon the doctrine.
I do not begrudge you your theories. I don't insist that you need to take the Bible literally. I once believed as you and was no less a child of God. As a Calvinist I didn't even realize I held competing positions (a biblicist in principle but not in practice).
I do approach Scripture with the presupposition that the actual text of Scripture determines its meaning so we will never agree on the Atonement.
But we do not have to agree.
I want others who pass by this thread to consider various Atonement theories - to include the Penal Substitution Theory of Atonement. BUT I also want them to consider that Scripture could teach what is written in its text.
I want them to understand that Scripture does not need those philosophies to make sence....that is, to understand God's Word as if it taught what is recorded in the text ("what is written").
THEN they can compare and decide for themselves which to accept.