Jesus doesn't come at the end of the millennium.
revelation 20:7-8 And when the thousand years are ended, Satan will be released from his prison and will come out to deceive the nations that are at the four corners of the earth, Gog and Magog, to gather them for battle; their number is like the sand of the sea.
Jesus comes after satan's little season
Revelation 20:11 Then I saw a great white throne and him who was seated on it. From his presence earth and sky fled away, and no place was found for them.
Again peter compares and contrasts 2 sets of heaven and earth. 1 Before the flood and 1 after the flood. 1 where the kosmos is destroyed by the flood which was "existing (imperfect tense) long ago", 1 where the ungodly are destroyed by fire which now exists (present tense).
2 Peter 3:5-7 For they deliberately overlook this fact, that the heavens existed long ago, and the earth was formed out of water and through water by the word of God, and that by means of these the world that then existed was deluged with water and perished. But by the same word the heavens and earth that now exist are stored up for fire, being kept until the day of judgment and destruction of the ungodly.
Peter's use of language is consistent with OT parabolic language of judgment, several examples include
Judgment againts Edom = literal, the heavens rotting = metaphorical
Isaiah 34:3-5 Their slain shall be cast out,and the stench of their corpses shall rise;
the mountains shall flow with their blood. All the host of heaven shall rot away,
and the skies roll up like a scroll.All their host shall fall,as leaves fall from the vine,
like leaves falling from the fig tree. For my sword has drunk its fill in the heavens;
behold, it descends for judgment upon Edom,upon the people I have devoted to destruction.
Judgment againts Babylon = literal, heavens trembling, earth shaken out of its place = metaphorical
Isaiah 13:13 Therefore I will make the heavens tremble, and the earth will be shaken out of its place,
at the wrath of the LORD of hosts in the day of his fierce anger.
Judgment against Ninevah = literal, hills melting, mountains quaking, earth heaving = metaphorical
Nahum 1:1-5 an oracle concerning Nineveh. The book of the vision of Nahum of Elkosh. The LORD is a jealous and avenging God;the LORD is avenging and wrathful;the LORD takes vengeance on his adversaries and keeps wrath for his enemies. The LORD is slow to anger and great in power,
and the LORD will by no means clear the guilty.His way is in whirlwind and storm, and the clouds are the dust of his feet. He rebukes the sea and makes it dry; he dries up all the rivers;Bashan and Carmel wither;the bloom of Lebanon withers. The mountains quake before him; the hills melt;
the earth heaves before him,the world and all who dwell in it.
Again you cannot provide and posts of mine where I go into detail about Titus. Interesting.......