The Cross of Christ is the sacrifice of Christ, and its by this Sacrifice that all who believe are redeemed.
John 3:16-17 (WEB):
(16) For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life.
(17) For God didn’t send his Son into the world to judge the world, but that the world should be saved through him.
Everybody is redeemed by Jesus' sacrifice, whether they believe or not. Some will have never heard of YHVH and Jesus, but Jesus was sent not to judge them but to save them. Being redeemed from the penalty for sin (death), God is then justified in restoring everyone to life (resurrection). After their resurrection, then they have a trial and judgement for eternal life - Hebrews 9:27 (WEB):
(27) Inasmuch as it is appointed for men to die once, and after this, judgment,
Acts 24:15 (WEB):
(15) having hope toward God, which these also themselves look for, that there will be a resurrection of the dead, both of the just and unjust.
Jesus will establish God's Kingdom on the earth, and teach the truth to everyone, and there wlll be a 1,000 years trial (Satan, the liar and deceiver, will be bound up to restrain him from deceiving people during that time). Then those that believe and remain faithful and obedient throughout the trial, including the strong testing at the end when Satan is released, will be rewarded with eternal life, but those that are unfaithful or disobedient will be punished with the second death - they will perish (be destroyed):
Romans 6:23 (WEB):
(23) For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.
Revelation 20:7-8 (WEB):
(7) And after the thousand years, Satan will be released from his prison,
(8) and he will come out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together to the war; the number of whom is as the sand of the sea.
Revelation 20:12-15 (WEB):
(12) I saw the dead, the great and the small, standing before the throne, and they opened books. Another book was opened, which is the book of life. The dead were judged out of the things which were written in the books, according to their works.
(13) The sea gave up the dead who were in it. Death and Hades gave up the dead who were in them. They were judged, each one according to his works.
(14) Death and Hades were thrown into the lake of fire. This is the second death, the lake of fire.
(15) If anyone was not found written in the book of life, he was cast into the lake of fire.
Christians are on a different path and have their trial starting after they are begotten again, before they are resurrected:
1 Peter 1:3 (KJV):
(3) Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead,
Galatians 2:20 (WEB):
(20) I have been crucified with Christ, and it is no longer I that live, but Christ lives in me. That life which I now live in the flesh, I live by faith in the Son of God, who loved me, and gave himself up for me.
Colossians 1:24-29 (WEB):
(24) Now I rejoice in my sufferings for your sake, and fill up on my part that which is lacking of the afflictions of Christ in my flesh for his body’s sake, which is the assembly;
(25) of which I was made a servant, according to the stewardship of God which was given me toward you, to fulfill the word of God,
(26) the mystery which has been hidden for ages and generations. But now it has been revealed to his saints,
(27) to whom God was pleased to make known what are the riches of the glory of this mystery among the Gentiles, which is Christ in you, the hope of glory;
(28) whom we proclaim, admonishing every man and teaching every man in all wisdom, that we may present every man perfect in Christ Jesus;
(29) for which I also labor, striving according to his working, which works in me mightily.