10 And the devil who deceived them was thrown into the lake of fire and brimstone, where the beast and the false prophet are also; and they will be tormented day and night forever and ever.
and the Devil, who is leading them astray, was cast into the lake of fire and brimstone, where are the beast and the false prophet, and they shall be tormented day and night-to the ages of the ages. (Rev.20:10, YLT)
And the Adversary who is deceiving them was cast into the lake of fire and sulphur where the wild beast and where the false prophet are also. And they shall be tormented day and night for the eons of the eons. (Rev.20:10, Concordant Literal New Testament, 1983)
...and the Adversary that had been deceiving them was cast into the lake of fire and brimstone, where [were] both the wild-beast and the false-prophet; and they shall be tormented day and night unto the ages of ages. (Rev.20:10, Rotherham Emphasized Bible, 1959
American Standard Version footnote: *Gr. unto the ages of the ages.
Revised Version, 1881 footnote: *Gr. unto the ages of the ages.
Bible Translations That Do Not Teach Eternal Torment
Does ages of the ages have an end? Christ's reign is "to the ages of the ages":
And the seventh messenger did sound, and there came great voices in the heaven, saying, 'The kingdoms of the world did become those of our Lord and of His Christ, and he shall reign to the ages of the ages!' (Rev.11:15, YLT)
But His reign is "until" He gives up the Kingdom to the Father:
24 Then the end will come, when He hands over the kingdom to God the Father after He has destroyed all dominion, authority, and power. 25 For He must reign until He has put all His enemies under His feet. (1 Corinthians 15)
So Christ's reign "to the ages of the ages" is not "forever and ever". Therefore the phrase "to the ages of the ages" can be understood of a limited time period that comes to an end. So those in the lake of fire are not punished there "for ever and ever" (Rev.20:10).
Also, "forever and ever" is nonsense. No time can be added to "forever".
When Christ's reign ends (1 Cor.15 above), this will lead to God being "All in all" (v.28). IOW everyone will be saved, as all will be "in Christ" (v.22).
Rev.21:5 He who was seated on the throne said, “I am making all new!”
2 Cor.5:17 Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all is become new.
Chapter Five
Why Can't Aionas Ton Aionon Mean Eternity?
"After all, not only Walvoord, Buis, and Inge, but all intelligent students acknowledge that olam and aiõn sometimes refer to limited duration. Here is my point: The supposed special reference or usage of a word is not the province of the translator but of the interpreter. Since these authors themselves plainly indicate that the usage of a word is a matter of interpretation, it follows (1) that it is not a matter of translation, and (2) that it is wrong for any translation effectually to decide that which must necessarily remain a matter of interpretation concerning these words in question. Therefore, olam and aiõn should never be translated by the thought of “endlessness,” but only by that of indefinite duration (as in the anglicized transliteration “eon” which appears in the Concordant Version)."
Eon As Indefinte Duration, Part Three
Berean Literal Bible
And the devil, the one deceiving them, was cast into the lake of fire and of sulfur, where the beast and the false prophet also are; and they will be tormented day and night to the ages of the ages.
Weymouth New Testament
and the Devil, who had been leading them astray, was thrown into the Lake of fire and sulphur where the Wild Beast and the false Prophet were, and day and night they will suffer torture until the Ages of the Ages.
Revelation 20:10 Interlinear: and the Devil, who is leading them astray, was cast into the lake of fire and brimstone, where are the beast and the false prophet, and they shall be tormented day and night -- to the ages of the ages.
If torment is "to" or "until" a certain age or ages, as per the versions above, then it ends before that age starts, so it is not for ever and ever.
If torment is "into" (EIS) these future ages, as the word EIS is often translated as "into", that does not necessarily mean it lasts for the entire duration of those ages, even if those ages are endless.
If torment is "into the ages of the ages", the torment makes entrance into those ages, not necessarily throughout the entire duration of them. Therefore the torment "into the ages of the ages" (e.g. Rev.20:10) is of an indefinite period of time.
Revelation 20:10 Interlinear: and the Devil, who is leading them astray, was cast into the lake of fire and brimstone, where are the beast and the false prophet, and they shall be tormented day and night -- to the ages of the ages.
eis: to or into (indicating the point reached or entered, of place, time, fig. purpose, result)...Definition: into, in, unto, to, upon, towards, for, among."
Strong's Greek: 1519. εἰς (eis) -- to or into (indicating the point reached or entered, of place, time, fig. purpose, result)
From other Scriptures it is clear that the torment ends.
https://www.tentmaker.org/books/hope_beyond_hell.pdf