And you seem to not understand what the word "one" means. In Hebrew the use here is "Echad" not "Yachid".
If God were simply positively 1 the word would be Yachid. God is Echad (united) and the Old Testament talks about this all over the place. You just do not see it or understand this.
King David knew of both Gods. Your Judaism has blinded you to scriptural truth.
Psalm 110.
2samuel 7:25 and 28
MANY other verses referencing more than 1 God.
"Here oh Israel, The LORD our God (the Father), the Lord (Jesus), are one echad (united).
"Let US make man in our image." Not the Father and angels. The Father and Jesus.