When is the judgment of fallen angels? The angelic “sons of God” are chained in darkness reserved “unto the judgment of the great day” (Jude 1:6; Gen. 6:1-4). “Great Day” is the day of Jesus’ return (Ac. 2:20. Rev. 6:17; 16:14), which puts the judgment of fallen angels at Christ’s return(Ac. 2:20. Rev. 6:17; 16:14). That’s why there is no mention of them during the Great White Throne Judgment (Rev. 20:11-15).
Because the judgment of fallen angels is at Jesus’ return they vanish from view. By the time of the “sheep and goat” judgment, they are already in the Lake of Fire. When Christ judges the generation still alive at His coming, it is suggested by “depart from Me you cursed, into the fire prepared for the devil and his angels” (Mt. 25:41), that the Devil and his fallen angels are already there (Rev. 20:2).
But Satan was not with the fallen angels when they were cast into the Lake of Fire. That is clear from his being the only one bound and chained for a thousand years (Rev. 20:1-2). Confirming this, the fallen angels do not reappear at the end of the thousand years when Satan is released for a time and then is cast into the Lake of fire (Rev. 20:7-10). After he is cast into the Lake of Fire (Rev. 20:10) the Great White Throne Judgment of mankind begins (Rev. 20:11-15). Satan or his fallen angels are never mentioned again.
Christ’s parable about the wheat and the tares is consistent with this, “all things that offend” (Mt. 13:38) would include the fallen angels as “spiritism” is the “energy” of the “mystery of lawlessness” that is the “deluding influence” in the end time. (2 Th. 2:2, 7-12. 1 Cor. 12:2. 1 Ti. 4:1. 1 Jn. 4:3). That creates the TARES among the good seed.
This also is consistent with “Know ye not that we shall judge angels?” (1 Cor. 6:3) Their Judges are the Kings and Priests raised in the First Resurrection (Rev. 20:4) just before the Millennial Kingdom begins (Rev. 20:4-6).
Isaiah 24:22 does not contradict this conclusion. “The host of the high” likely refers to the priests and temple soldiers of the powerful and mighty who exalted themselves above everyone else (Is. 65:5; Lk. 18:9-14). These sacrificed to demons in the high places, therefore there is where God will cut them down. Then He gathers them into Sheol to await Judgment Day.
21 And it shall come to pass in that day, that Jehovah will punish the host of the high (04791 מָרוֹם marowm ) ones on high (04791 מָרוֹם marowm), and the kings of the earth (0127 אֲדָמָה ‘adamah) upon the earth (0127 אֲדָמָה ‘adamah ).
22 And they shall be gathered together, as prisoners are gathered in the pit, and shall be shut up in the prison; and after many days shall they be visited.
23 Then the moon shall be confounded, and the sun ashamed; for Jehovah of hosts will reign in mount Zion, and in Jerusalem; and before his elders shall be glory. (Isa. 24:21-23) ASV
To recap. The Kings and Priests raised up in the first resurrection (gathering rapture of the church) judge the fallen angels. They are cast into the lake of fire at Christ’s coming after Armageddon.  The goats among the generation alive at Christ’s coming then join the fallen angels in the Lake of Fire. Satan is not with them, he alone is bound and imprisoned for a thousand years.  He is cast into the Lake of Fire just before the Great White Throne Judgment. That is why no angels are mentioned during the Great White Throne judgment in Revelation 20:11-15.
Its possible Satan’s Nephilim Fallen angels are among the “kings…captains…and mighty” slain at Armageddon. Notice these are mentioned first, then “the flesh of all, free and slave, both small and great” (Rev. 19:18). Contrary to the “ruling” of the Fourth Lateran Council in 1215, angels are corporeal (1 Cor. 15:40). There is no compelling reason to accept the Roman Catholic Church’s pontification on this, but most Protestants do:
The clear pronouncement of Holy Scripture that the angels are spirits (pneumata; Matt. 8:16; 12:45. Luke 7:21; 8:2; 11:26. Acts 19:12; 23:8. Eph. 6:12. Heb. 1:14), who do not marry (Matt. 22:30), are immortal (Luke 20:35–36) and invisible (Col. 1:16), may be “legion” in a restricted space (Luke 8:30), and like spirits, have no flesh and bones (Luke 24:39).-Bavinck, H., Bolt, J., & Vriend, J. (2004). Reformed Dogmatics: God and Creation (Vol. 2, p. 456). Grand Rapids, MI: Baker Academic.
However, that hypothesis is a hasty generalization fallacy that confuses “spirits” with “angels” as these are distinguished from each other (Ac. 23:8-9). The lying spirit who fools the prophets (1Kings 22:21-22) is nothing like the angels who ate and drank with Abraham (Gen. 18:1-8) or sat under a tree speaking to Gideon (Judges 6:11-12). Rather than conjure up physical forms to be seen, it appears they have cloaking technology (2Kings 6:17) and appear in our matrix without walking through doors or walls just as Jesus did in his physical resurrection body (John 20:19-20). Jesus eats a fish to contradict any suggestion He is a spirit (Luke 24:36-43).
Angels are always represented as physical and the theory they have God like power to create living bodies contradicts the declaration God alone has that power (Dt. 32:39). Rather, scripture reveals there are portals that can connect earthly and heavenly realms. Jacob saw angels walking through a portal on a ladder through the “gate of heaven” (Gen. 28:12, 17). John went through a similar door to enter heaven (Rev. 4:1). So did the chariots of fire that took Elijah away, a swirling energy vortex (2 Kings 2:11). Christ and His heavenly army will enter our Matrix through an opening in the sky (Rev. 19:11) perhaps similar to when the clouds concealed His departure during his Ascension (Acts. 1:9).
When the “complete” (5046 τέλειος teleios) and “partial” (3313 μέρος meros) (1 Cor. 13:10) touched each other [“kingdom of God came in power (Mk. 9:1)] during the Transfiguration, Moses and Elijah step into our Matrix still physical as Peter confirms by wanting to build tents for them (Mk. 9:4-5). [Satan had tried to prevent the resurrection of Moses (Jude 1:9)]. It is a massive violation of Occam’s razor sola scripturists ignore these scriptures to perpetuate the error proposed by the Fourth Lateran Council in 1215.
“Spirits of demons” implies angelic bodies (1 Cor. 15:40) contain within them an immaterial spirit (Rev. 16:14). Spirits and angels are distinguished from each other (Ac. 23:8-9). The hapax legomen λειτουργικὰ πνεύματα “ministering spirits” in Hebrews 1:14 notwithstanding. This is not a reference to angelic nature, but to their function as minsters of the spirit. If these were immaterial spirits, then God wouldn’t have to make them spirits after creation (Ps. 104:4. Heb. 1:7).
Nothing about New Jerusalem coming down from heaven implies an “immaterial city”, it follows neither would their likely builders be immaterial (Rev. 21:10-27). If one cannot be physical in heaven, why didn’t Paul realize he wasn’t still in his own body while in third heaven? (1 Cor. 12:2, 4). The description of this matrix as a “partial” requires it is less substantial as “the complete”. The “teleios” contains dimensions of revelation of God we lack (1 Cor. 13:8-12). If anything is “immaterial”, it be us ghostly photons consisting in the Infinite Mind of God the Eternal Son held together by His thought (Col. 1:17. Ac. 17:28). As the “Word of God” Jesus makes concrete what Triune YHWH God conceives (2Cor. 4:6. Gen. 1:1).
Let’s not confuse the “spirits of demons” (Rev. 16:14) with angels still having “celestial bodies” (1Cor. 15:40).
Unclean spirits and demons wandering tombs etc. craving corporeality, are the spirits of Nephilim who did not corrupt the image of God in man but weren’t permitted to reenter the dimension of heaven as the flood waters killed all flesh alive on the earth (Gen. 7:21-23). Included among these are the evil hybrid offspring of the angels (Gen. 6:4). Desperately craving corporeality, they pathetically roam the wastelands possessing anything they can, insects (2Kings 1:2), animals (Lk. 8:33) or men (Lk. 8:30-32).
7 Now when the thousand years have expired, Satan will be released from his prison
8 and will go out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together to battle, whose number is as the sand of the sea.
9 They went up on the breadth of the earth and surrounded the camp of the saints and the beloved city. And fire came down from God out of heaven and devoured them.
10 The devil, who deceived them, was cast into the lake of fire and brimstone where the beast and the false prophet are. And they will be tormented day and night forever and ever. (Rev. 20:7-10 NKJ)
When Christ returns with His holy Angels the nations that survived Armageddon are judged with the sheep and the goats (Mt. 25:31-33). We must infer a third group exists we could call the “undetermined”. The sheep enter life eternal (Mt. 25:34), the goats cast into eternal fire (Mt. 25:41). Those who are neither goats or sheep enter the Millennial Kingdom unregenerate and procreate. All who begin sinning die, access to the tree of life denied (Is. 65:19-25. Gen. 3:22-24. Rev. 2:7; 22:2, 14). At the end of the 1,000 year reign of Christ is there another world wide test. Gog and Magog lead the extremities of the planet in an attack on the people of God (Rev. 20:7-9).
There are parallels with the Days of Noah and the millennial reign of Christ (Is. 65:20-25). Just as the antediluvians rebelled against Creator God because they preferred evil (Gen. 6:5), Gog and Magog and the nations with them do the same (Ezek. 38:1-23; 39:1-29. Rev. 20:7-9). Man (not Satan) is deceived they can prevail against God despite the lesson to the contrary (Rev. 6:12-14).
Its possible technology increases during the millennial reign of Christ. That seems implied by nations being pronged “for a season and a time” (Dan. 7:12) retaining the ability to wage war even after a thousand-year reign of Christ (Rev. 20:7-9). Therefore, the ability to manipulate DNA for immortality likely possible without God.
In any event, Satan again deceives humanity they can successfully rebel against God (Rev. 16:13-16; 20:7-10).
How dark the heart choosing slavery to sin (Gen. 6:5) rather than the perfect liberty free “from the bondage of corruption in glorious liberty of the children of God (Rom. 8:19-21).
He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things? (Rom. 8:32 KJV)
But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. (1 Cor. 2:9 KJV)