It's all an earlier time and we are being told "what will happen" We know none of this has happened yet. This is prophecy. But we need to know which verses describe the end and which verses bring them back to John in his present state of writing about what will happen.
Revelation 21:1 "And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.
John is still describing what he is seeing at the end after Judgement Day. He notes that that the first heaven and earth are passed away.
Revelation 21:3 "And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God."
He's still describing and he hears that great voice..
Revelation 21:4 "And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away."
That great voice is telling him that God shall wipe away their tears, telling them that there will be no more death, etc because the former things are passed away.
The next voice coming from the throne takes us to John's present -
Revelation 21:5 "And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful."
He tells him that he makes all things new and to write: for these words are true and faithful.
We have to see when something is being described, back to John's present state and what is simply a reiteration.
Revelation 21:6 "And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely."
Christ states it is done. So anything afterwards are just descriptions of the New Jerusalem and warnings to the reader.
Revelation 21:7 "He that overcometh shall inherit all things; and I will be his God, and he shall be my son."
We know that happens at Judgement
Revelation 21:8 "But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death."
And we know that happens at Judgement.
And we know death is done away with. So the second death is final. Which again we know happens at Judgement as we saw in chapter 20.
Revelation 22:10 "And he saith unto me, Seal not the sayings of the prophecy of this book: for the time is at hand."
Revelation 22:11 "He that is unjust, let him be unjust still: and he which is filthy, let him be filthy still: and he that is righteous, let him be righteous still: and he that is holy, let him be holy still."
He's talking to the reader of this prophecy. He's stating to whomever is reading, if they want to still be unjust then still be unjust, etc. He that is righteous, let him be righteous still. That is is talking in the present.
Revelation 22:12 "And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be."
He hasn't returned yet so this isn't the end. Again, he's reiterating what will happen to those who overcome and those who don't. You asked for a verse showing this isn't the end, well, we can see that it's not the end. He's talking about his return.
Revelation 22:13 "I am Alpha and Omega, the beginning and the end, the first and the last."
Revelation 22:14 "Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city."
Revelation 22:15 "For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie."
And of course the city is without those because the former things are passed away.