Gal 3:20 Now a mediator is not [a mediator] of one, but God is one.
In case an explanation is needed, there is only one true God and God is only one. Not two. Not three. God is one.
As noted above the man Jesus Christ identified Himself by name and indicated that He existed before Abraham. Using simple cuts from third persons, or those further removed, in an attempt to trump, or contradict what the person Himself says about Himself is illogical.
"In case an explanation is needed, there is only one true God and God is only one. Not two. Not three. God is one."
Of course God is one, the same as I am. Nevertheless, the concept of trinity accounts for the essence of and the instantiation of persons/individuals in the 2 worlds.