A couple of interesting points you have raised. With regards to the king of kings reference there are three in the OT which refer to earthly kings
Ezra 7:12 Ezekiel 26:7 Daniel 2:37
However, these are mortal kings who were, for a time in power over the whole earth.
With regards to Jesus
Isaiah 9:7 (New International Version)
7 Of the increase of his government and peace
there will be no end.
He will reign on David's throne
and over his kingdom,
establishing and upholding it
with justice and righteousness
from that time on and forever.
The zeal of the LORD Almighty
will accomplish this.
Now, I just conclude this
John 10:30 (New International Version)
30 I and the Father are one."
John 14:8-9 (New International Version)
8 Philip said, "Lord, show us the Father and that will be enough for us."
9 Jesus answered: "Don't you know me, Philip, even after I have been among you such a long time? Anyone who has seen me has seen the Father. How can you say, 'Show us the Father'?
All the best, Stephen