Did Satan ever have authority? Maybe. I would be willing to see some verses. Paul says that we used to walk according to the system of this world, according to the prince of the power of the air. But this seems more like being directed by deception rather than authority. People who walk according to this world system do so voluntarily, not under compulsion by an authority.
But maybe I need to study more.
Jesus did not question Satan's ownership of the kingdoms of the earth when He was tempted in the desert (Mathew 4:9).
Jesus preached the new covenant, but lived in the old one.
That is why he sent his disciples only to the "lost sheep of the house of Israel" (Mathew 10:6).
The New covenant began with His resurrection, and after that He sent His disciples to the whole world.
Acts 1:8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
Between Rome and Jerusalem all of Jesus' original disciples other than John were all killed, and had not Jerusalem been destroyed most if not all of the Christians might have also been killed.
I think most of the book of Revelations, whether from a heavenly or earthly standpoint, is about the destruction of Jerusalem.
This includes the four horsemen, the bowls of wrath, the two witnesses and the first six trumpets.
The seventh trumpet however is about the rise of Christ's kingdom from the ashes of old Jerusalem:
Revelations 11:15 And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
So now we find ourselves in a world where the power of Satan can be seen yet still,
and I you said that you struggle to see that Satan is chained.
I think that matter is better understood when the nature of Christ's kingdom is understood.
Christ's kingdom is eternal, meaning without time.
It is present and heavenly, not future and earthly.