You said "the second person of the Trinity that assumed human nature, body and soul." The 2nd Person of the Holy terinity who took human nature did not cease to be God. Holy Trinity is God. Father is God. Son is God, Holy Spirit is God. You are re-defining God as being only the Holy Trinity.
That means that all three Hypostates are somehow "lesser" than "complete" God, or that God is a "compound" of three divine "ingredients" that, combined in the Godhead "make" God.
"You are re-defining God as being only the Holy Trinity"
The church proclaims, "God in three persons". My post affirms that and that Jesus is fully God in the undivided divine essence, however there is a certain order in subsistence and operation of the three persons in the divine Being as well as certain personal attributes that distinguish the three persons of the trinity. The Father is neither begotten by, nor proceeds from any other person; the Son is eternally begotten of the Father, and the Holy Spirit proceeds from the Father and the Son from eternity. There is a subordination in respect to order and relationship, a logical order of derivation, but not to any priority of time or essential dignity. The divine essence is not an independent existence alongside the three persons.