You said....."Jesus has a God thus cannot be God".
Jesus who is God, the second of the trinitarian Godhead took the form of a man during His incarnation.
We read about that in
John 1:14 as well as
Phil 2:7.....This is called the kenosis. It is where Christ Jesus who is equal to and in the form of God... emptied Himself and became subservient to the Father.
While in this subservient role....as a man...Jesus could easily claim the Father is His God. It's who Jesus prayed to, it's through whom Jesus learned from, it's who through Jesus worked, It's who Jesus glorified....and so on.
During the kenosis Jesus gave up the glory He had with the Father....asking in a prayer....John 17:5 And now, Father, glorify me in your own presence with the glory that I had with you before the world existed......Phil 2:9-11 shows that restoration.
So, yes, Jesus can be God and have a God.