The doctrine of God our Savior is the same as the doctrine of Christ.
Tit 2:10 Not purloining, but shewing all good fidelity; that they may adorn the doctrine of God our Saviour in all things.
Heb 6:1 Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God,
2Jo 1:9 Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.
Since all scripture is given by the inspiration of God and is profitable for doctrine...then I would go with the answer you gave in the last part of your post. The doctrine of God is the whatever the Bible teaches about God but especially the new covenant and how all of the OT has led up to Christ in types and shadows.
__________________
His banner over me is LOVE....
My soul followeth hard after thee....Love one another with a pure heart
fervently.
Jesus saith unto her, Said I not unto thee, that, if thou wouldest believe, thou shouldest see the glory of God?
To be a servant of God, it will cost us our total commitment to God, and God alone. His burden must be our burden... Sis Alvear