They won't be destroyed. The scripture says they'll be tormented day and night forever.
Here is my understanding of Rev.20:10 and how I came to that conclusion...it says that the Devil will be cast into “the lake of fire” and “tormented day and night for ever and ever"...if the Devil were to be tortured for all eternity, God would have to preserve him alive, but the Bible says that Jesus will “destroy him.” Hebrews 2:14, KJ
So with that in mind, the symbolic fiery lake represents “the second death.” Revelation 21:8
This is not the death first mentioned in the Bible...death because of Adam’s sin...death from which one may be released by a resurrection....1 Corinthians 15:21, 22
Because the Bible does not say that “the lake of fire” would release those in it, “the second death” must mean another kind of death, an irreversible one...
In what sense are those in “the lake of fire” tormented eternally? At times, “to torment” can mean “to restrain” someone...once when Jesus confronted the demons, they cried out, “Art thou come hither to torment us [restrain us in the abyss] before the time?” Matthew 8:29; Luke 8:30, 31; KJ
So all of those in “the lake” will suffer the “torment” of everlasting restraint, or “the second death.”
In the Scriptures fiery torment is associated with destruction and death...for example, in the Greek Septuagint translation of the Hebrew Scriptures the word for torment..basanos...is several times used with reference to punishment by death...Eze. 3:20; 32:24, 30
Concerning Babylon the Great, the book of Revelation says, “the kings of the earth...will weep and beat themselves in grief over her, when they look at the smoke from the burning of her, while they stand at a distance because of their fear of her torment...Rev. 18:9, 10
As to the meaning of the torment, an angel later explains...“Thus with a swift pitch will Babylon the great city be hurled down, and she will never be found again.” (Rev. 18:21
So, fiery torment here is parallel with destruction, and in the case of Babylon the Great, it is everlasting destruction...Rev. 17:16; 18:8, 15-17, 19
But regardless of torment or destruction...they will never be allowed to wreak havoc on the earth or in the heavens ever again...