Revelation 19 and Revelation 20 are not (and cannot) be chronological. This is part of your confusion here.
Revelation 19:17-18 is climactic, “I saw an angel standing in the sun; and he cried with a loud voice, saying to all the fowls that fly in the midst of heaven, Come and gather yourselves together unto the supper of the great God; That ye may eat the flesh of kings, and the flesh of captains, and the flesh of mighty men, and the flesh of horses, and of them that sit on them, and the flesh of all men, both free and bond, both small and great. And I saw the beast, and the kings of the earth, and their armies, gathered together to make war against him that sat on the horse, and against his army. And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone. The loipoy (or remaining ones) those left behind were slain with the sword of him that sat upon the horse, which sword proceeded out of his mouth: and all the fowls were filled with their flesh.”
This is complete wholesale total destruction - for those left behind. There are no survivors!
The feasting part of the marriage supper of the Lamb is a symbolism depicted the destruction of the wicked. Why can this not be a symbolic depiction of the return of Christ and the events that accompany it (including the destruction of the wicked)?
The first part of the narrative outlines a detailed account of the assignment given to “the fowls that fly in the midst of heaven” by the heavenly messenger. The “fowls” are instructed to “come and gather” themselves “together unto the supper of the great God” in order that they would “eat”:
1. The flesh of kings,
2. The flesh of captains,
3. The flesh of mighty men,
4. The flesh of horses, them that sit on them,
5. The flesh of all men, both free and bond, both small and great.
This passage powerfully and solemnly reveals the full extent of the devastation that is to be focused upon the wicked on the day of God’s wrath. In perfect keeping with the rest of Scripture, this narrative graphically shows us that the destruction that occurs will be immediate, absolute and total and that, at this stage – after “the marriage of the Lamb” (Rev 19:7) – everyone left behind will be completely consumed; the birds of heaven filling themselves with “the flesh of all men.” Significantly, the suffix “both free and bond, both small and great” is added in order to fully impress the enormity and all-inclusive nature of this feast.
The whole thrust of this reading surrounds a climactic end to the world. Like the rest of Scripture, it records the complete rescue of the saints in the “marriage of the lamb” and the complete destruction of the wicked when the fowls consume the entire wicked left behind. The passage makes no allowance for goats-survivors in this great destruction passage or mortals squeezing into a supposed future millennium. This reading seems to fit in with the scriptural pattern of an all-consummating Coming - all the wicked being consumed.
The second coming of the Lord Jesus Christ will be a unique day in the annals of human history and unprecedented in its all-consummating character. Obviously, no other day has ever seen the end of the world and the final complete defeat of every last enemy of righteousness, truth and Almighty God. Neither has any other day seen the destruction of all wickedness by way of fire before. Notwithstanding, the Lord draws our specific attention to two notable days in human history to compare it with, and to fully illustrate the character and finality of this all-consummating day. These two particular days are familiar to most and are found in Holy Writ (both in the Old Testament), and give us an unparalleled insight into the nature, extent and detail of judgment on that impending last day. While, evidently there is no previous individual bygone historic example of a total global annihilation of the wicked by fire, these two individual days, when joined together, vividly portray what will occur on the final day of time. These two former days being (1) the day that Noah entered into the ark and (2) the day that Lot was rescued out of Sodom.