Yes, God is one being, one person --- not 3-in-one as Trinitarians believe. One means one, not 2,3,4,etc. Yes, you say you believe God is one yet he's really 3-in-one - three is not one - one is not three and never will be.
Jesus is the one sent ---- someone else had to send him ---- that someone who sent him is God therefore Jesus is not God.
Jesus said to them, “If God were your Father, you would love me, for I came from God and I am here. I came not of my own accord, but he sent me. [John 8:42]
The one sent is not equal to the one who sent him: Truly, truly, I say to you, a servant is not greater than his master, nor is a messenger greater than the one who sent him. [John 13:16]