Who will end up in Hell?

Let's start with those who do NOT go to hell. All those raised at the first resurrection and those who go to Heaven without seeing death will avoid hell (the lake of fire). They will still be purified - tested - by fire (Mark 9:49, 1 Corinthians 3:13).

For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. 1 Thessalonians 4:16-17

This is the "resurrection of the just".

And thou shalt be blessed; for they cannot recompense thee: for thou shalt be recompensed at the resurrection of the just. Luke 14:14

And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory. And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other. Matthew 24:30-31

These are the elect, the overcomers, the just, the barley harvest. They will reign in Heaven for 1000 years.

Blessed and holy is he that hath part in the first resurrection (the resurrection of the just): on such the second death hath no power, but they shall be priests of יהוה [Yahweh, our god] and of Messiah, and shall reign with him a thousand years. Revelation 20:6

Those who do NOT go to Heaven are asleep in their graves during this 1000 years.

But the rest of the dead lived not again until the thousand years were finished. Revelation 20:5

After the 1000 years reign in Heaven, after the Holy City comes to this Earth, there will be a 2nd resurrection, raising the "wicked" to judgement and fire:

And have hope toward Elohim, which they themselves also allow, that there shall be a resurrection of the dead, both of the just and unjust. Acts 24:15

And when the thousand years are expired, Satan shall be loosed out of his prison, And shall go out to deceive the nations which are in the four quarters of the earth, Gog and Magog, to gather them together to battle: the number of whom is as the sand of the sea. And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from יהוה (Yahweh) out of heaven, and devoured them. And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever. And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them. And I saw the dead (former dead, now raised up in the 2nd resurrection), small and great, stand before יהוה; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works. And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works. And death and sheol were cast into the lake of fire. This is the second death. Revelation 20:7-14

This also shows that the multitude as numerous as the "sand of the sea", under the influence of Satan, will try to conquer the city. They are not incapacitated, they are rebellious. Then fire comes down from Yahweh, divine judgment from the great white throne.

The wicked are outside the city.

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. For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie. Revelation 22:14-15

The gates are kept open so all who are pure can enter, but the wicked cannot enter (until they become pure).

And the gates of it shall not be shut at all by day: for there shall be no night there. And they shall bring the glory and honour of the nations into it. And there shall in no wise enter into it any thing that defileth, neither whatsoever worketh abomination, or maketh a lie: but they which are written in the Lamb's book of life. Revelation 21:25-27

ALL is revealed to the wicked. There is no more hiding behind rationalizations or ignorance. They are finally laid bare to the consequences of their lives. This is Hell. This is unmitigated guilt and separation. This is the second death. This is the "great multitude" thrown into the lake of fire.

The sea (lake) "gave up the dead". "Gave them up" is not the same as consumed them until they were ashes. After the "wicked" are cleansed, the sea gives them up, reborn and pure. Eventually, all have been purified. There are none left and at that moment, death itself is destroyed. ALL have been able to enter the gates as they are purified. Some may take a few hours, some a few days, months, years? Only our Father knows. Only as they recognize and admit their error and accept Yahweh can they be cleansed and enter the Holy City.

This viewpoint is dependent on the conviction that ALL will be restored. If you aren't yet convinced of that, prayerfully study God's Plan of the Ages, then come back to this study.