You either missed or ignored the point.
Try again - or don't. I don't care which.
And never mind that Paul qualifies there, as elsewhere in his writings, WHAT gospel he is referring to....
Ephesians 3:6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
Notice..."the gospel:"
Ephesians 3:7 Whereof I was made a minister, according to the gift of the grace of God given unto me by the effectual working of his power. 3:8 Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ; 3:9 And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ: 3:10 To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God,
Note also that Paul also relates that "God...created all things by Jesus Christ" and then relates that the revelation of this unsearchable mystery concerns said things somehow:
10 To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God,
The revelation of this mystery that Paul is preaching among the Gentiles has to do with these principalities and powers in heavenly places - they were now being informed of this mystery.
Paul is calling this mystery he is preaching among the gentiles the gospel he is preaching among them.
While fools continue to conclude their supposed 2P2P notions, these passages point to another aspect of God's plan and purpose - this one an heavenly one - that Paul calls the gospel he is preaching among the Gentiles.
This is why the invention of Preterism - having read right past this other aspect of God's Two-Fold Plan and Purpose: Prophecy (The Earth) and Mystery (The Heavenly) having read right past the Mystery aspect of God's Two-Fold Purpose, the fools ended up seeing holes in Matthew 24 that are not really there.
Holes they then also had to solve for by their same, own fool reasoning.
Holes that ignorance of this mystery that Paul preached among the Gentiles ends one up seeing.
So, off they went to the wisdom of men - secular history, with its equally endless speculations...
The Three Stooges attempting to solve for the sinking row boat they themselves caused to begin to sink.
Attempting to solve for said sinking now, by drilling holes in the boat.
Preterism and its "doing the history" clowns - a circus act if there was one.
The issue is God's Two-Fold Purpose concerning positions of authority over BOTH the Earth, and Heaven...
Colossians 1:16 For by him were all things created,
that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: 1:17 And he is before all things, and by him all things consist. 1:18 And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence. 1:19 For it pleased the Father that in him should all fulness dwell; 1:20 And, having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say,
whether they be things in earth, or things in heaven.
One is...
Daniel 2:44 And in the days of these kings shall the God of heaven set up a kingdom, which shall never be destroyed: and the kingdom shall not be left to other people, but it shall break in pieces and consume all these kingdoms, and it shall stand for ever. 2:45 Forasmuch as thou sawest that the stone was cut out of the mountain without hands, and that it brake in pieces the iron, the brass, the clay, the silver, and the gold; the great God hath made known to the king what shall come to pass hereafter: and the dream is certain, and the interpretation thereof sure.
The other is...
Ephesians 1:19 And what is the exceeding greatness of his power to us-ward who believe, according to the working of his mighty power, 1:20 Which he wrought in Christ, when he raised him from the dead, and set him at his own right hand in the heavenly places, 1:21 Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come: 1:22 And hath put all things under his feet, and gave him to be the head over all things to the church, 1:23 Which is his body, the fulness of him that filleth all in all.
One is...
Matthew 6:9 After this manner therefore pray ye: Our Father which art in heaven, Hallowed be thy name. 6:10 Thy kingdom come. Thy will be done in earth, as it is in heaven.
And...
Acts 3:19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord; 3:20 And he shall send Jesus Christ, which before was preached unto you: 3:21 Whom the heaven must receive until the times of restitution of all things, which God hath spoken by the mouth of all his holy prophets since the world began.
The other is...
1 Thessalonians 4:16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: 4:17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
Philippians 3:20 For our conversation is in heaven; from whence also we look for the Saviour, the Lord Jesus Christ:
Colossians 3:4 When Christ, who is our life, shall appear, then shall ye also appear with him in glory.
Why the PLANNED interruption of His Plan and Purpose as to the Earth?
Becuase before this is possible - "Thy kingdom come. Thy will be done in earth, as it is in heaven."
...this must first be solved for...
Ephesians 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.