Revelation 20:1-7 (Thousand Years) is nothing more than a human explanation of God's eternal realm of no physical time, (Non-Literal)
You will closely note that this is in the Lords spiritual realm 100% Angel, Heaven, Devil, The Souls, The Dead.
This non-literal 1,000 years is taking place Now in the Lords spiritual
Satan is currently bound from "One Specific Purpose" and this purpose only, "Deceiving The Nations To Battle" as verse 7 shows how he is loosed at the end of the tribulation to deceive the nations to the final battle.
Verse 9 below is the last day final judgement by fire, 2 Peter 3:10, Zechariah 14:12
All believers old and new Testament alike partake in the "First Resurrection" on the last day, there are "Two" resurrections on this last day?
"First" eternal life, "Second" eternal damnation, John 5:28-29, Dan 12:1-2
20 And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand.
2 And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years,
3 And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.
4 And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.
5 But the rest of the dead lived not again until the thousand years were finished. This is the first resurrection.
6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
7 And when the thousand years are expired, Satan shall be loosed out of his prison,
8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog, and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them.