Some alternate translations have:
Young‘s Literal Translation: ―punishment age-during.
Rotherham Translation: ―age-abiding correction.
Weymouth Translation: ―punishment of the ages.
Concordant Literal Translation: ―chastening eonian."
eonian, "αἰώνιος...lasting for an age...partaking of the character of that which lasts for an age, as contrasted with that which is brief and fleeting... (also used of past time, or past and future as well) Derivation: from G165;" G166 αἰώνιος - Strong's Greek Lexicon
The "eternal" (eonian) fire that burned Sodom went out long ago:
Jude 1:7 As Sodom and Gomorrah and the cities about them in like manner to these committing ultra-prostitution, and coming away after other flesh, are lying before us, a specimen, experiencing the justice of fire eonian."
"2851. kolasis...Short Definition: chastisement, punishment..."
"In the late 2nd century/early 3rd century, Clement of Alexandria clearly distinguished between kólasis and timoria: “For there are partial corrections [padeiai] which are called chastisements [kólasis], which many of us who have been in transgression incur by falling away from the Lord’s people. But as children are chastised by their teacher, or their father, so are we by Providence. But God does not punish [timoria], for punishment [timoria] is retaliation for evil. He chastises, however, for good to those who are chastised collectively and individually” (Strom. 7.16)."
From Here to Eternity: How Long is Forever?
Earlier in the book of Matthew the same author wrote:
Mt.1:21 And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins.
Mt.2:6b ...my people Israel.
From page 26 the passage in Matthew 25 is considered at:
https://www.tentmaker.org/books/hope_beyond_hell.pdf
Following are various translations of Matthew 25:46:
Translation of the New Testament from the Original Greek Humbly Attempted by Nathaniel Scarlett Assisted by Men of Piety & Literature with notes, 1798:
"And These will go away into onian punishment: but the righteous into onian life."
The New Testament by Abner Kneeland, 1823:
"And these shall go away into aionian punishment*: but the righteous into aionian life."
The New Covenant by Dr. J.W. Hanson, 1884:
"And these shall go away into onian chastisement, and the just into onian life."
Youngs Literal Translation of the Holy Bible, 1898:
"And these shall go away to punishment age-during, but the righteous to life age-during."
The Holy Bible in Modern English, 1903
"And these He will dismiss into a long correction, but the well-doers to an enduring life."
The New Testament in Modern Speech, 1910:
"And these shall go away into the Punishment 1 of the Ages, but the righteous into the Life 1 of the Ages."
1. [Of the Ages] Greek "aeonian."
A Critical Paraphrase of the New Testament by Vincent T. Roth, 1960
"And these shall go away into age-continuing punishment, but the righteous into life age-continuing."
The Restoration of Original Sacred Name Bible, 1976
"And these shall go away into age-abiding *correction, but the righteous into **age-abiding life."
The Twentieth Century New Testament, 1900
"And these last will go away into onian punishment, but the righteous ?into onian life."
The People's New Covenant, 1925
"And these will depart into age-continuing correction, but the righteous, into age-continuing life."
Emphatic Diaglott, 1942 edition
"And these shall go forth to the aionian 1 cutting-off; but the RIGHTEOUS to aionian Life."
The New Testament of Our Lord and Savior Jesus Anointed, 1958
"And these shall go away into agelasting cutting-off and the just into agelasting life."
The New Testament, a Translation, 1938
"And these will go away into eonian correction, but the righteous into eonian life."
The New Testament, A New Translation, 1980
"Then they will begin to serve a new period of suffering; but God's faithful will enter upon their heavenly life."
Concordant Literal New Testament, 1983
And these shall be coming away into chastening eonian, yet the just into life eonian."
Rotherham Emphasized Bible, 1959
"And these shall go away into age-abiding correction, But the righteous into age-abiding life."