"All authority hath been given unto me in heaven and on earth."
Don't take Scripture out of context. This is Mat.28:18 and immediately following in vs. 19,20 is the Great Commission given to his disciples (and us), ending "and lo I am with you alway, even unto the end of the world."
The authority is given to them who will take the gospel to the ends of this earth, and the promise of his presence will be with them that do.
No jest, I believe Him when He said His kingdom was not of this world and would not be visible to the eye. I believe it when we're told that we've come to a mount that might not be touched with the hand or seen with the eye or is in any way tangible to our bodily senses. You have a very carnal view of His kingdom.
He will set up His Kingdom on this world. If not many promises and prophecies are negated. And the Scriptures will be found to be in error.
The Place of His Return
Zechariah 14:4 And his feet shall stand in that day upon
the mount of Olives, which
is before Jerusalem on the east, and the mount of Olives
shall cleave in the midst thereof toward the east and toward the west,
and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south.
The Mount of Olives shall be split in two when the feet of Jesus descend upon it. This has not happened yet, but it will. He WILL reign.
Isaiah 2:2 And it shall come to pass in the last days,
that the mountain of the LORD'S house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it.
3 And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem.
4 And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more.
--This is on THIS earth, not on a new earth, but THIS one.
He will judge the nations. He will beat their swords into plowshares. There will be no more war.
He shall reign! But He is not reigning now.
What is happening now?
Christ is Lord!
Philippians 2:9 Wherefore God also hath highly exalted him, and given him a name which is above every name:
10 That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth;
11 And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.
--But note: Very few are subject to Him as Lord. That day is still future.
In the future all will be required to acknowledge Him as King and Lord.
It is a future event!
What about now?
Ephesians 2:2
the prince of the power of the air,
the spirit that now worketh in the children of disobedience:
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.
2 Corinthians 4:3 But if our gospel be hid, it is hid to them that are lost:
4 In whom
the god of this world hath blinded the minds of them which believe not.
2 Corinthians 10:3 For though we walk in the flesh, we do not war after the flesh:
4 (For
the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds

5 Casting down imaginations, and
every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
Now: Satan is the god of this world. He is the one who is reigning on this earth.
Now we war against: principalities, powers, the rulers of the darkness of this world, spiritual wickedness in high places.
Christ is not reigning; Satan, the god of this world is reigning, and we are in a fierce battle against him.
Therefore we need to take upon ourselves spiritual weapons (Eph.6:10-18), and fight a spiritual battle (2Cor.10:3-5).
If Christ reigned no such battle would exist, but it does.