It seems you’re straying close to “modalism,” which I’m told is a heresy.

Concerning a few of those verses which would speak of God sending Himself and being greater than Himself and being beside Himself, these are among some of the mind-bendingly impressive feats of which the eternal and infinite God who created time and space and logic and (effectively) reality itself is capable. God continuing to be His infinite self is something easily understood; descending from that eternal infinity and imposing the limitations of finite time and space and (particularly) human biology (such as our brain’s limited memory and processing power, particularly in the years between our conception and adulthood) on Himself while still being that infinite self (“Before Abraham was, I am!” remember?) is a lot more difficult to comprehend, and yet that’s what God did when coming to us as Jesus. Such is the aspect of God’s being eternal and infinite known as omnipresence: being simultaneously in not only more than one place (and time) but in all times and places while filling none of them, a feat so impressive that our very words in any language struggle to describe it (such as my using “simultaneously” meaning “at the same time” just now to describe something eternal which is by definition beyond time’s constraints). On the other hand, given that even some of our greater authors (e.g. C.S. Lewis) have written works of “self-insert” fiction deploying themselves into their fictional worlds as an author avatar (e.g. Professor Digory Kirke in the Narnia Chronicles), is it really so difficult to comprehend that an author can in some sense both be his avatar and yet be greater than his avatar?

Also, given that said author avatar ascended body and soul into our eternal Author and Creator’s eternal Heaven with Him in Acts 1:9 (which is where the analogy to human authors ultimately meets its limit—e.g. Lewis didn’t have the power to bring Kirke out of his books and into our world), is it so difficult to understand how God can be enthroned next to Himself in eternity? Contrary to your previous claim in your now-closed comments section, the concept of eternity is not some Greek innovation on the Hebrew concept of our “everlasting” God: in fact, a lot of the Greeks (Aristotle, for one) believed our world to be un-created and co-eternal with God (to the extent they could be said to believe in one unified God; Aristotle had his concept of a Prime Mover on which Thomas Aquinas would later base his own philosophy) whereas the Hebrews already knew God exists “from everlasting to everlasting” (Psalm 90:2 and at least six other places) and yet the heavens and earth were doomed to “wear out like a garment” and be replaced accordingly (Psalm 102:25-26, and this was also later reaffirmed in Isaiah 51:6). That our world has a beginning and ending (contrary to “Dust In The Wind” by Kansas, not even the earth and sky last forever) but God does not was already known; and on the rare occasions where they applied the term “everlasting” to decidedly more temporal things like the hills (Deuteronomy 33:15) and foundations of the earth (Micah 6:2), the term was used generally the way we mean when we say “indefinitely” now, i.e. “until someone [God, in the Hebrews’ case] determines otherwise.” I can live with the description of God as being “from everlasting to everlasting” being alternatively translated as “from indefinite to indefinite” in regard to the Hebrews’ struggle to describe God’s being eternal.

Of course, as with many arguments about the Trinity, whether all of this makes God the Father, God the Son, and God the Holy Spirit all one “person” or three “distinct persons” depends on how you’re defining terms like “distinct” and “person” there. Really, such pedantry (as some would think of it) is the origin of the entire debate. No matter how much one parses such terms (along with others like “essence” and “divinity”) in debate, however, the Scriptures you cite still make each God out to be the same God as stated to Israel all the way back in Deuteronomy 6:4 with its paradoxical use of the plural Eloheinu (“our Gods”) with the singular syntax of echad (“is one”).