After the millennium there will be no more suffering or death,

that is what Rev. 21:4 says. So the rebels, those too proud and rebellious to submit to God, will be destroyed at the end of the millennium. Satan will lead them in a rebellion, and they will be defeated, forced to stand before the white throne, hear their sentence, and be destroyed. The idea that they will stand before the white throne for many years, is not correct. They will have the opportunity to repent during the millennium, during that time they will not be standing all the time, but working, planting crops and other work, and learning the Bible. And they will be judged all that time. And the sentence, life or death, will be pronounced at the end, from the white throne, they will be standing there maybe a few minutes or hours, but not years.
But that is a minor difference between us, the main thing is that we both agree that those unbelievers will have a chance for salvation, and not be condemned by what they believed when they died, that would be a terrible view of God, and yet that is the monstrous theory that many of our Christian brethren believe.