Okay...so according to what you have just said, there is a Father, a Son, and a Holy Spirit. Still, your only assertion that the Father is the only true God, is that Jesus referred to Him as the only true God, and that it is unclear that the Holy Spirit is the true God.
You see, I have just turned it around. Nonetheless, the words of Jesus would seem to support your supposition, but the lack of anything credible regarding the Holy Spirit leaves that one to a draw.
But now you have sighted other scriptures. I thought you were not going to do that. I did suggest we move on, and I am completely fine with it, but clearly things are unresolved here. What is it that you are looking for? Would you like scripture, documentation, or should we both make supposition?
Since you have already done so, I will make my own supposition:
"A tree is known by its fruit." While it is true that the case for Godship of the Son and the Holy Spirit is arguable, it is not without reason or even evidence: Jesus performed miracles and rattled off knowledge only God could produce. The Holy Spirit, likewise, all throughout the ages. But I prefer what He (God) has given me: personal, spiritual proof. Not that I could prove any of it to you, an atheist, or anyone for that matter. But the whole of the written word supports it as God's truth, because of the same manner of personal spiritual (as well as physical) witness testimony, which cannot be denied. So, if any of it is credible, then I have a case to be heard, whether received or not.
But back to the fruit. By the creation, if we can agree that it represents God's truth...it begins in the garden. By this we know that a son or a child are "of" their father, and a tree bearing fruit is even more, for the fruit is not just "of" the tree, but is a part thereof. And if we believe, we believe that the multitude of witness testimonies all come down to two family trees by two fathers: one flesh and one spirit. Yet to give voice to a fruit or a son, would he not praise the branches and the root, though they are One...just as the scriptures say?
Therefore what God has joined together, let not man separate.