"The OP makes the point that God wants to save everyone and then asks why conservatives believe God’s will can be thwarted and why it cannot be fulfilled in the next life.
Let’s summarize the points before which Jeff and company continually freeze like Bambi in the headlights.
(1) The Philippain hymn pictures everyone in the universe, righteous and unrighteous, bowing before Christ and making the saving confession. Paul teaches that no one can sincerely confess Jesus as Lord apart from the Holy Spirit (1 Corinthians 12:3).
(2) The universal confession envisaged must be a saving confession because (a) the hymn in based on the divine invitation to universal salvation in Isaiah 45:22-23 and (b) the alternative explanation is the absurd assumption that the unrighteous dead are portrayed as making this saving confession before a lever is pulled and they are then sucked down to Hell.
(3) The hymn in Revelation 5:13 similarly envisages all humanity, living and dead, worshiping Jesus and God. But how did the evil dead get to Heaven to sing this hymn? John tells us that the gates of the New Jerusalem are permanently open (21:25), so that those outside, the evil dead (22:15) can enter and be saved (22:15).
“God our Savior…desires everyone to be saved and to come to a knowledge of the truth (2 Timothy 2:4).”
Indeed, various NT texts imply the possibility of postmortem repentance and salvation (e. g. 1 Peter 3:19; 1 Corinthians 15:38-29), texts to be discussed later. But is God the Savior only of the righteous or of both the righteous and the unrighteous? Paul gives this thrilling inclusive response:
“The living God…is the Savior of all people, especially of those who believe (2 Timothy 4:10).” Here "especially means “more immediately” and leaves the door open for postmortem repentance.
as famed evangelical apologist C. S. Lewis eloquently puts it: “The gates of Hell are locked from the inside.”
Many more NT texts confirm this glorious hope."