I believe that this verse speaks of the fate of the devil, in its context.
However, Revelation 20:10 would seem to indicate a different fate for the devil, if you are interpreting the first verse correctly.
I understand what Revelation 20:10 means in context, scripturally, for it refers to the length or period of torment for the devil, not his ending. The devil shall suffer (moment to moment), without reprieve until he is ashes.
Heaven is eternal, no doubt, for God Himself is Eternal Life, and the redeemed will be indwelt by God throughout eternity, but the wicked are not so indwelt, but are found to be outside of God, rather than abiding in God. And since they are found outside of God, they are found outside of eternal life.
How then are the wicked to have eternal existence?
As shown, the words, of Revelation 20:10, "even for ever and ever", are Koine Greek, "εις τους αιωνας των αιωνων", which when seen in their context, locally and globally through the scripture [KJB], do not always mean eternal, but can mean limited in time, and can even deal with distance, or even spacial ["world"].
Can an "αιων" [aiwn, aeon, in either time, distance or space] come to an end? Yes, even as Paul shows in Hebrews:
Hebrew 9:26 KJB - For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself.
Hebrew 9:26 KJB - επει εδει αυτον πολλακις παθειν απο καταβολης κοσμου νυν δε απαξ επι συντελεια των αιωνων εις αθετησιν αμαρτιας δια της θυσιας αυτου πεφανερωται
Notice, "end of the world [aeon]". Notice again:
Titus 2:12 KJB - Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world;
Titus 2:12 KJB - παιδευουσα ημας ινα αρνησαμενοι την ασεβειαν και τας κοσμικας επιθυμιας σωφρονως και δικαιως και ευσεβως ζησωμεν εν τω νυν αιωνι
Notice, "in this present world [aeon]", which indicates that there is an end to the current "world", or existence, and another "world" [aeon], or existence, to follow after it. Thus and "aeon" can come to an end, and is not necessarily eternal. See also "since the world began", "before this world", "this present evil world", "this world", in Matthew 12:32, Matthew 13:22, Matthew 13:39-40 (2), Matthew 13:49, Matthew 24:3, Matthew 28:20, Mark 4:19, Mark 10:30, Luke 1:70, Luke 16:8, Luke 18:30, Luke 20:34-35 (2), John 9:32, Acts 3:21, Acts 15:18, Romans 12:2, 1 Corinthians 1:20, 1 Corinthians 2:6-8 (4), 1 Corinthians 3:18, 1 Corinthians 8:13, 1 Corinthians 10:11, 2 Corinthians 4:4, Galatians 1:4, Ephesians 1:21, Ephesians 3:9, Ephesians 3:21, Ephesians 6:12, 1 Timothy 6:17, 2 Timothy 4:10, Tit 2:12, Hebrews 6:5, Hebrews 9:26; and etc. We now see that "aeon's" can begin, and end, and are not always ongoing without ceasing, and thus context always determines the length, distance, existence, etc.
Notice how the Bible uses the word "for ever":
Jonah 2:6 KJB - I went down to the bottoms of the mountains; the earth with her bars was about me for ever: yet hast thou brought up my life from corruption, O LORD my God.
Jonah 2:6 (2:7) (so-called) LXX - κατέβην εἰς γῆν, ἧς οἱ μοχλοὶ αὐτῆς κάτοχοι αἰώνιοι, καὶ ἀναβήτω φθορὰ ζωῆς μου, κύριε ὁ θεός μου.
In both distance and time, it is impossible for the word "for ever" in Jonah to be eternal, or without end. Not only does earth have limited space [thus
"ends of the earth", dry land is earth, see Genesis 1], but Jonah was only 3 days and 3 nights, timewise, in the belly:
Jonah 1:17 KJB - Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights.
Therefore, in either case, "for ever" is limited, in this instance, in distance and time.
In Deuteronomy 23:3 KJB, “forever” means 10 generations. It can also mean “as long as he lives,” or “to death.”; thus see 1 Samuel 1:22, 28; Exodus 21:6; Psalm 48:14 KJB.
The redeemed will have eternal life, because Jesus is eternal life, but the wicked will never have eternal existence:
Psalms 21:4 KJB - He asked life of thee, and thou gavest it him, even length of days for ever and ever.
Ecclesiastes 8:13 KJB - But it shall not be well with the wicked, neither shall he prolong his days, which are as a shadow; because he feareth not before God.
Iniquity must be purged and cleansed from the universe, and it will not happen until the wicked cease to be:
Isaiah 22:14 KJB - And it was revealed in mine ears by the LORD of hosts, Surely this iniquity shall not be purged from you till ye die, saith the Lord GOD of hosts.
Psalms 37:10 KJB - For yet a little while, and the wicked shall not be: yea, thou shalt diligently consider his place, and it shall not be.
When will these verses be fulfilled in your understanding:
Malachi 4:1 KJB - For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly, shall be stubble: and the day that cometh shall burn them up, saith the LORD of hosts, that it shall leave them neither root nor branch.
Malachi 4:3 KJB - And ye shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I shall do this, saith the LORD of hosts.
Days of Noah, Days of Lot (Sodom and Gomorrah):
Did the global flood of Noah kill all of the finally impentient outside of the Ark in one single instant of time?, or was there not rather various lengths of time, and degrees of injuries sustained throughout, that people continued to receive and live through, until all were finally destroyed from the face of the earth? with some instantly perishing, and others taking days to finally die either by beast, other men attempting to escape their doom fighting for the highest ground, starvation, thirst, hurling and heaving earth, or finally drown beneath the black depths ...
In
2 Peter 2:5 [see also
2 Peter 3:6] KJB, Peter says "flood upon the world", yet in the Koine Greek, it is "κατακλυσμον κοσμω", a 'cosmic cataclysm'. Such devastation and destruction as has never been known, and will never again be known [by water], but will again be by fire. If one were to read
Genesis 7-8 KJB carefully they will see that it took some time for all [human-kind] outside of the ark to finally perish, and not all perished at the same time. The wages for sin is death, even from
Genesis 2:17 KJB, but the final punishment, being death, is preceded by terrors, anguish, torment, all limited and depending upon the deeds done in the body [
Romans 2:6;
jude 1:15 KJB], as it is written.
So to die of thirst in such a cataclysm takes several days, while being crushed by a large piece of exploded land, or tree, or debris is near instantaneous. Each is just. Each received the length of time in torment, suffering, that was due, and both received the final end, death.
The "punishment" is indeed "eternal". For the "wages of sin is death", that being the "second death".
The "torment", or the "suffering" unto that death, is limited. The suffering or torment is not eternal, as I have shown in the case of Jesus Christ, who took upon Himself the sins of the whole world. His suffering though tremendous, more than any other could endure [for just our own sins would crush us], and yet, it was limited. Hence the phrase, "once suffered", meaning it is in the past, and is over and done with, thus it was limited in time.