gave you the list of nations-related action verses in #379. Obviously life goes on post-judgment. Nobody's trapped like a bug in aspic forever. The nations emerge from the fire renewed and walk in peace in 21:24-26, and come for healing in 22:2. The gates are always open. Simple storyline, follows the Christological pattern of cleansing and healing.
22 I did not see a temple in the city, because the Lord God are its temple. 23 The city does not need the sun or the moon to shine on it, for the glory of God gives it light,and the Lamb is its lamp. 24 The nations will walk by its light, and the kings of the earth will bring their splendor into it.25 On no day will its gates ever be shut, for there will be no night there. 26 The glory and honor of the nations will be brought into it. 27 Nothing impure will ever enter it, nor will anyone who does what is shameful or deceitful, but only those whose names are written in the Lamb’s book of life.
Nothing about nation's emerging from the fire here....
And what do we know about the book of Life?
"And all who dwell on earth will worship it, everyone whose name has not been written before the foundation of the world in the book of life of the Lamb who was slain."
"The one who conquers will be clothed thus in white garments, and I will never blot his name out of the book of life. I will confess his name before my Father and before his angels."
"And if anyone's name was not found written in the book of life, he was thrown into the lake of fire."
"And if anyone takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book."
Well, that is certainly inconvenient for the universalist. You can be blotted out of the book. You can forfeit your place in the holy city by taking away from the truth told here.