"I AM" has a very simple meaning, and it is indeed what you said, "is, was, will be". Yeshuah satisfies that definition, because he was in the beginning, he currently is, and is coming. The angel also satisfies that definition, because he was, he currently is, and then also came down to deliver his people from the Egyptians. And of course, the Father also satisfied that definition, because he was, he currently is, and is coming also, because his presence will descend unto the new earth, and he will live among us. Yehovah is indeed an angel, because through him came the old covenant that foreshadowed the new and greater covenant that was to come through Yeshuah. The first was merely just a shadow, the second was the reality. Greater honor is given unto the name of Yeshuah, than unto the name of Yehovah. This is why the name of Yehovah is no longer used to worship God, because a new and greater than has been given unto us to worship God, the name of Yeshuah, which in fact, includes the name of Yehovah in his own name, because Yeshuah means, "Yehovah delivers". Read my study on the name of God here,
The True Pronunciation of YHVH and the Name of the Messiah | Wisdom of God . And you will also learn about the true pronunciation of the tetragrammaton, which is "Yehovah".
I read your lengthy piece teknon and have no problem with calling Jesus Yeshua, though I have my preference of Jesus because the name is not the defining attribute of almighty God.
Personally I believe you are incorrect in calling Yehovah (YHWH) an "angel" in the sense of being lesser than Yeshua (as you say) or having a name of lesser significance.
Where all this greater glory has been given unto Yeshuah, because unlike the angel Yehovah, Yeshuah suffered and died for his people, thus making his name worthy of greater exaltation than the name of Yehovah,
There are different ways of addressing Almighty God, the - LORD God - is YHWH-Elohim in a connective way and because YHWH is based upon the total tenses of the 1st person representation of the verb "to be" YHWH is a descriptive name or actually an adjectival name meaning GOD IS ETERNAL with no beginning and no end. ELOHIM - within the Godhead are 3 distinct persons which is why Elohim is plural (in thousands of places in a standalone way). The LORD God therefore refers to the Trinity and those distinct persons within that Godhead as ALL eternal.
The angel of the LORD MALAK-ELOHIM. MALAK translated as "angel" is functional as "messenger" or one who communicates as the function as one can see in the verses containing the name.
Genesis 16:10 And the angel of the LORD said unto her, I will multiply thy seed exceedingly, that it shall not be numbered for multitude.
This is called a theophany.
This is why Yeshua is called the word - the Logos - in the New Covenant scripture because He being God Himself communicates God to man in His totality
Logos Grk. The expression of an inward thought.
John 1
1 In the beginning was the Word (Logos) and the Word was with God, and the Word was God.
2 The same was in the beginning with God.
3 All things were made by him; and without him was not any thing made that was made.
John 1:18 No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him.
So wherever we see The Angel of the LORD in the OC scripture (MALAK-ELOHIM) it is the Logos within the Triune Godhead communicating with man.
Genesis 16:11 And the angel of the LORD said unto her, Behold, thou art with child, and shalt bear a son, and shalt call his name Ishmael; because the LORD hath heard thy affliction.
There must be a mediator between the God and man.
1 Timothy 2:5 For there is one God, and one mediator between God and men, the man Christ Jesus;