I personally believe there is one throne that both the Father and the Son is seated based on this verse in Revelation 3:21 "and sat down with my Father on his throne."
Then the subordinate relationship between Father and Son is not
eternally subordinate.
Do not over-complicate it or overthink it.
But in Revelations 4 mentions there is "one sitting" on the throne. And Revelations certainly does make the distinction between "one sitting" and "the Lamb" (Revelations 5:13, 6:16).
Again, If the Lamb and/or God is sitting on the exact same throne then that is
proof, not just mere evidence of an equality, not a subordination.
With that in mind, I will outline some opposing problems:
1. The Divine Nature is not bound to a spatial location (the throne in heaven) or confined to union of the human nature by the Son-person, then jump from point A to point B (Jeremiah 23:23-24, 2 Chronicles 2:6, 1 Kings 8:27). The Divine Nature is omnipresence and is equally present everywhere at all times and in all places. This means that the logical standpoint is "present at hand" accordance to the throne in heaven and "present at hand" according to the human nature and not vice versa. Because the throne and the human nature is not omnipresence.
It is correct that God exists outside of and external to that which He created and, therefore, the relationship between God the Father and God the Son is not confined to the Son being the word made flesh. God is omni-attributed.
What is not correct is "...the throne.... is not omnipresent." That is wrong. The "throne" is not a chair sitting in heaven. The throne
is heaven.
Isaiah 66:1
Thus says the LORD, “Heaven is My throne and the earth is My footstool. Where then is a house you could build for Me? And where is a place that I may rest?
Matthew 5:34-35
"But I say to you, make no oath at all, either by heaven, for it is the throne of God, or by the earth, for it is the footstool of His feet, or by Jerusalem, for it is the city of the Great King."
This should be read within the context of the verse first verse of the Bible.
Genesis 1:1
In the beginning God created the heavens and the earth.
God made the heavens and the earth and the heavens are His throne and the earth is His footstool and Jesus is seated on that throne that is the heavens in the heavens ruling over the earth and there is not one fraction of a millimeter over which He/he is not LORD/Lord.
More importantly, all the following comments you've posted about Revelation have to do with soteriology and eschatology, but you have failed to distinguish that fact from capital-T Theology (the nature of God). Jesus prior to creation being created is a much different Jesus than the one who surrendered his claim of equality with God and emptied himself (he did it - it was not to him or forced upon him in any way by another), took the form of a bondservant, being made in the likeness of men (Php 2).
Now I do not know where you personally and specifically fall on my next point, but I am going to speak to it preemptively. A lot of people wrongly imagine Jesus was not omnipresent while one earth in a physical human body, but scripture gives us plenty of evidence to think otherwise. He sees and hears Nathaniel from far away. He knows the past, present and future stretching across millennia, not just the limits of his earthly life and memory. He knows the thoughts/minds or others both commonly (the mind of fallen man) and personally (the mind of specific individuals). People anthropomorphize Jesus in bad ways AND they fail to correctly understand the nature of time and space - or omnipresence - because time and space are functions of gravity, or more accurately
singularity.
God the Father AND God the Son are THE Creator of singularity.
More importantly, any limited locality Jesus may have had on earth or "in" heaven or "in" revelation (remember: he is the revealer, he existed external to the revelation of Revelation).
I would also submit
Jesus' "human nature" is omnipresent but that is fodder for a separate post. We're made like Jesus, not the other way around. We're a temporal creation of the extra-temporal Jesus and Jesus did things in his earthly body and with his earthly bodies we cannot or do not do. It's a
base error in logic to think from the creature to the creator and assume the former's attributes apply to the latter.
2. Then who was John seeing in Revelations 4:3?
The Revealer of that Revelation.
The one who is sitting on the throne isn't named. But no one can see the Father (1 Timothy 6:16), the Son is also in the invisible image (Colossians 1:15) according to the Divine Nature, and we have only seen the Son's physical image (John 1:18) according to the human nature. So, based on this, I would say that the "present at hand" accordance to the throne in heaven, is a manifestation of theophany and the Lamb is a manifestation of christophany.
I encourage you to think this through because your own words
prove the subordinate role is soteriological and eschatological and not eternal. Let me clarify that. Salvation and end times are (sort of) eternal conditions in the sense that once resurrected and past the transformation where we are raised incorruptible and eternal there is no going backwards. Our salvation, once complete, will be unending BUT Jesus is much more than our Savior. Jesus is Lord first. His being Savior applies only to those who are saved. To all others he is NOT savior BUT he is always and everywhere Lord. Every knee will bow and confess him as Lord and his Lordship is eternal. All creatures everywhere for all time will always and everywhere bow and acknowledge his Lord ship. They will not all bow and confess him as Savior.
His Lordship is eternal.
His Saviorship is also eternal but limited only to the saved and after their salvation is complete so too is Jesus' role as Savior. His Saviorship takes on a completed aspect that his Lordship does not possess - or it is more accurate to say his Lordship
exceeds.
Another thing I want to mention is from Athanasian Creed
No creed has authority over scripture. I subscribe to that creed but I will not entertain it for the purpose of this discussion because it is
extra-biblical, and unnecessary.
That the Son is eternal.
Psalm 90:2 Before the mountains were born or you brought forth the whole world, from everlasting to everlasting you are God.
Again: look at what you just posted. Psalm 90:2 does not state his sonship is everlasting. Furthermore, the phrase "
everlasting to everlasting" is not synonymous with "
eternal." The word "everlasting" is unidirectional (in this case the starting point is the creation of the world). Eternity is bi-directional, or omni-directional. Up, down, north, south, forward, backward, before, after are ALL created features of created creation. They do not exist in eternity.
Take for instant Hebrews 1:10-12 for example, the Son-person (who is the LORD) is being compared to a garment.........
Youo are again using a soteriological/eschatological example and failing to make the necessary distinction to consider the
eternal.
Eternal or after the resurrection?
Hebrews 13:8 Jesus Christ is the same yesterday and today and forever.
Hebrews 1:5 For to which of the angels did God ever say, “You are my Son; today I have become your Father”? Or again, “I will be his Father, and he will be my Son”?
There is no "yesterday" or "today" in eternity.
Radical improvements and changes are necessary when considering eternal Christology. Temporal Christology is not identical to eternal Christology; it is a subset of it. While Jesus is here on earth e is different than "while" in eternity. While "in" heaven he is different still (on earth, in heaven, before creation means there are three different aspects of Jesus, and they are not identical). The Revealer of Revelation was not in Revelation or his revelation while he revealed Revelation. The Revealer is always external to his revelation, just as I am not my posts and you are not yours.