You forgot one!
first. Scripture was not written in verse chapter form. Men added these. so you should read it like a book.
second. If you study rev 19 and 20 you will see a sequence. (especially if you remove the verse chapter form)
Rev 19:
19 And I saw the beast,
the kings of the earth, and
their armies, gathered together to make war against Him who sat on the horse and against His army. 20 Then
the beast was captured, and with him the false prophet who worked signs in his presence, by which he deceived those who received the mark of the beast and those who worshiped his image. These two were cast alive into the lake of fire burning with brimstone. 21 And the rest were killed with the sword which proceeded from the mouth of Him who sat on the horse. And
all the birds were filled with their flesh.
If we stop here. You might have a point. But fortunately for those of us who really want to know. we can see it does not stop here. Because chapter 20 starts like this.
1
Then I saw an angel coming down from heaven, having the key to the bottomless pit and a great chain in his hand. 2 He
laid hold of the dragon, that serpent of old, who is the Devil and Satan, and bound him for a thousand years; 3 and
he cast him into the bottomless pit, and shut him up, and set a seal on him, so that he should deceive the nations no more till the thousand years were finished. But after these things he must be released for a little while.
You see, IT IS IMMEDIATELY AFTER THIS BATTLE, AND Christ's RETURN WHEN SATAN IS BOUND. for how long?? 1000 years.
the battle you are speaking of does not happen until the end of the 1000 years:
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[
b] the beast and the false prophet
are. And they will be tormented day and night forever and ever.
so we see, After the war of NATIONS in which they try to attack Jerusalem and are defeated by Christ's return (in which the birds are full of their flesh) we then see the 100 year kingdom. THIS HAS NOT HAPPENED.
After this. Satan is released. Another war is ATTEMPTED. but is stopped before it even gets going.
THEN the earth is destroyed and a new heaven and new earth (following judgment day)
You see, The THEN at the start of chapter 20 shows that it was a continuation of Thought to john. Not a new chapter or idea. it is saying. This happened first, THEN that happened.