I believe the Bible, correctly translated & interpreted, teaches eventual universalism as the final destiny of all human beings since Adam, after all have been delivered from "hell" & saved through Jesus Christ & Him crucified.
The reference to Hebrews 9:27 does not speak of "an expiration date" for salvation or God's love. After death comes judgement for all, sinners & saints. Judgement is a good thing:
"When your judgments come upon the earth, the people of the world learn righteousness." (Isa.26:9)
The Greek word for "chastening" here can mean correction:
The Lord is acquainted with the rescue of the devout out of trial, yet is keeping the unjust for chastening in the day of judging. (2 Pet.2:9)
Heb.9:27 says it is appointed to men once to die. Does that deny men can die twice? No. Does it say "only" once? No. If New England is appointed to play the Buffalo Bills twice, does that deny they won't meet again in the playoffs? No. How many times did those raised before the general resurrections die?
I think, in light of the Rapture theory, many Christians would disagree with the statement that 100% of mankind will die and face judgment. Not only that, but Hebrews 9:27 does not say men are "only" going to die once. Lazarus, for one, is a Biblical example of one who died twice & the book of Revelation speaks of the "second death"."
Heb.10:28 A man that hath set at nought Moses' law dieth without compassion on the word of two or three witnesses: 29 of how much sorer punishment, think ye, shall he be judged worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
Stoning to death is not a very sore or longlasting punishment. People suffered far worse deaths via the torture methods of the eternal hell believing Medieval Inquisitionists and the German Nazis under Hitler.
Therefore, if the writer of Hebrews believed the wicked would be punished with something so monstrous as being endlessly annihilated or tormented, he would not have chosen to compare their punishment to something so lame as being stoned to death. Clearly he did not believe Love Omnipotent is an unfeeling terminator machine or sadist who abandons forever the beings He created in His own image & likeness so easily.
Heb.1:2a in these last days has spoken to us in His Son, whom He appointed heir of all
Heb.1:3b When He had made purification of sins, He sat down at the right hand of the Majesty on high
Heb.2:2b every transgression and disobedience received a just penalty
Heb.2:6 But one in a certain place testified, saying, What is man, that thou art mindful of him? or the son of man, that thou visitest him?
7 Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands:
8 Thou hast put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him.
9 But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.
14 Therefore, since the children share in flesh and blood, He Himself likewise also partook of the same, that through death He might render powerless him who had the power of death, that is, the devil,
15 And might free those who through fear of death were subject to slavery all their lives.
https://www.tentmaker.org/books/hope_beyond_hell.pdf
Scholar's Corner: The Center for Bible studies in Christian Universalism