Bible study shows that the first part of Revelation 20:5, "The rest of the dead didn’t live until the thousand years were finished", is believed by Bible scholars to be an interpolation:
Probably crept into the text by accident in the fifth century; at first a marginal comment made by a reader expressive of his thought, later copied into the text by transcribers who failed to distinguish between the text and the comment.
It is not found in any manuscripts older than the seventh century.
Not found in any Greek manuscript of earlier date than the fifth century. Nor is it found in the ancient Syriac.
The Syriac-Peshito, the mother tongue of Jesus and the apostles, written in the first or second century and is older than any Greek manuscript extant, also repudiates this clause.
It is wanting, too, in the Vatican No. 1160, a manuscript of special clearness and harmony with the most ancient ones.
Even if you treat it as a true sentence of Scripture, it has to be interpreted in harmony with the rest of Scripture, which means you have to consider who "the rest of the dead" are - they are everyone except the resurrected Church that had just been described in the previous verse as living in heaven, seated on thrones, reigning and judging with Jesus for 1,000 years. Jesus and the Church will be regining for 1,000 years over the rest of mankind (the rest of the dead), blessing and judging them. The non-interpolated part of Revelation 20:5 says that those living and reigning with Jesus are those that were resurrected in "the first resurrection". By saying that the rest of mankind will not live until the end of the 1,000 years (bearing in mind that this is most likely not true Scripture) should be interpreted to mean that they will not have perfect and eternal life until after the judgement at the end of the 1,000 years.
Satan is bound up for the 1,000 years and released at the end of that time. Why? Because the rest of the dead are resurrected at the beginning of that 1,000 years to be blessed by Jesus and the Church, to be brought back to human perfection and to have faith in God and Jesus. Unlike the present age, where Satan is free to deceive mankind and unrighteousness abounds, Satan is bound so that he cannot deceive anyone during the 1,000 years, and Jesus will rule with with righteousness. The "rest of the dead" (having been alive for around 1,000 years) are then judged according to their works during those 1,000 years.
The resurrection of "the rest of the dead", the second resurrection, is described in Revelation 20:13 (WEB):
(13) The sea gave up the dead who were in it. Death and Hades gave up the dead who were in them. They were judged, each one according to his works.
The dead in the sea includes all those that died during the world-wide flood in the days of Noah. Everyone who has died will be resurrected (the sea and death and Hades "gave up the dead") - except the Christian Church because they had already been resurrected! They are then "judged" at the end of the 1,000 years; they are judged based on their works during the 1,000 years (verse 12). Those whose names have not made it into the "book of life" - the record of who is judged worthy of eternal life - will then suffer a second death (verses 14-15, symbolically described as being thrown into the lake of fire), and then there will be no more death, so death is also symbolically described as also being destroyed (symbolic because death cannot burn or die, let alone die a second time!).
The long life of up to 1,000 years after they are resurrected, is the first chance of eternal life for the majority of mankind, and it is their jugdement 'day'. For Christians, our first chance is when God gives us the gift of faith in Jesus, and we we are begotten again by God. Our judgement day is our life after baptism into Christ's death. A second death is God's judgement for those not worthy of eternal life.
The argument you present has many errors.
1. Jesus spoke Hebrew/Aramaic not Syriac /Peshito
Revelation 20
King James Version
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.
10 And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.
11 And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
12 And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
14 And death and hell were cast into the lake of fire. This is the second death.
15 And whosoever was not found written in the book of life was cast into the lake of fire.
Let us for a moment assume your sources are correct (assume not accept): The fact of two resurrections are unambiguously clear without verse 5!
Verse 6 calls those of the first resurrection blessed. So are you saying verse 6 is invalid also?
The verse 6 resurrected reign with Jesus for a thousand years. Is this invalid also?
After 1,000 years Satan is released and goes and deceives again masses of humanity- defeated and cast into the lake of fire where the beast and false prophet already are (not were)!
God establishes His GWT raises the rest of the dead and then judges them!
So verse five merely describes teh fact of what takes place.
1. Teh martyred during the trib are raised and called blessed,
2. they reign for 1,000 years
3. After the 1,000 years, another rebellion that is defeated.
4. Teh GWT is set and the rest of the dead are resurrected!