Or we could say it this way:
New Heavens, New Earth & New Jerusalem did NOT Begin AFTER "The 1,000 Years " Millennium Ends.
"The 1,000 Years" is simply the first thousand years of the New Heavens, New Earth & New Jerusalem.
And these all began at Christ's Return, marked in history by the destruction of Old Covenant Jerusalem in 70AD.
MC and MB are two different persons within two different internet communities, (one gated, one not). But they both approach the matter much the same way. Notice how this approach openly contradicts itself, bringing self-refutation:
"Even though chapter 20
comes after chapter 18, Revelation 20 is a
recapitulation of this same event. It is not to be
looked at in a chronological time frame!
"
~MC, May 30

"But, heaven and earth would be
destroyed at the end of the millennium according to
Revelation 21:1f. This for me places the time of
Babylon's judgment at the end of the millennium." ~MC, June 26
Let's look at Rev 21:1 "And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea."
MC misses: there is nothing here to indicate that Rev 21:1 happens AFTER the 1,000 year Millennium ends; nothing except that Rev 21 comes after Rev 20.
"I dont think that Revelation 20 is sequential " ~MB, June 3
"...The New Jerusalem comes after the 1000 years. ..." ~MB, June 5
Evidently, both MC and MB, are thrown off by the (uninspired) insertion of chapter&verse demarcations into John's Revelation and so they conclude that Revelation 21 describes things that are sequential to Revelation 20: that is, they conclude that New Heavens, Earth & Jerusalem's beginning is sequential to the 1,000 year Millennium's ending.
Its this very mental blockage, I believe, that holds back a few preterist Christians from a credible handling of the brief passage mentioning the 1,000 year Millennium.
All one really has to do is forget about the chapter&verse markings between Rev 18 and 22 to find that:
EACH "AND I SAW ..." FOLLOWING THE FALL OF BABYLON (Rev 18:2) NARRATES YET ANOTHER MINI-VISION DETAILING MORE DIRECT CONSEQUENCES OF BABYLON'S FALL
Its listing the reasons for all the rejoicing in Heaven over Babylon's Fall (Rev 19:1-2...). The 1,000 year Millennium found only in Rev 20:1-10 is simply one immediate consequence among many of Babylon's Fall -each of which having their beginning with Babylon's End. This is why preterist Christians get so excited over Old Covenant Jerusalem's 70ad destruction:
Bablyon's Ending was the the Beginning of all those blessings envisioned thereafter, each introduced with John saying, "I SAW..."
Rev 20:1-10's events, Millennium of 1,000 years etc, is just one such blessing listed. All the other "I saw" descriptive mini-visions also begin at Babylon's 70ad Fall, including the appearance of the New Heavens, New Earth & New Jerusalem, (regardless of what one understands about Rev 20:1-10).
At Bablyon's Fall circa 70ad, each of these events have their beginning:
*Babylon's judgment and plagues, losses of merchandising, etc., ~Rev 18: 1-24
*Rejoicing in Heaven over Babylon's Fall, Marriage Supper of the Lamb ~Rev 19:1-9
*Jesus & the Saints begin their conquest & judgment of the nations ~Rev 19:11-16
*Fowls invited to eat the carcasses of the slain armies ~Rev 19:17-18
*The Beast & False Prophet conquered, then cast into Lake of Fire; fowls eating the flesh of their armies ~Rev 19:20-21
*The Devil bound & cast into the abyss below for 1,000 years, (beneath everyone's feet - Romans 16:20) ~Rev 20:1-3
*1,000 years begin, Resurrection of saintly martyrs who resisted Beast during Tribulation, 1st of 2 resurrections mentioned ~Rev 20:4-6
.....[Details also given about events occuring at the END of the 1,000 years ~Rev 20:7-10]
.....[......a) Resurrection of "the rest of the dead," ie, of everyone but the saintly martyrs who resisted the Beast during the Tribulation]
.....[......b) Satan's brief release and subsequent judgment into the Lake of Fire where the Beast & False Prophet had been cast]
*Commencement of Great White Throne Judgement ~Rev 20:11-15
*Arrival of New Heavens & New Earth ~Rev 21:1
*Arrival of New Jerusalem ~Rev 21:2-Rev 22:5
The Text of Revelation itself suggests that the 1,000 years follow the Fall of Babylon - listed among the list of direct consequences thereof and as one of Heaven's various reasons for rejoicing over Babylon's Fall. It has been shown by many capable commentators that Revelation's "Babylon" = Old Covenant Jerusalem. Presently popular attempts, (among some preterists), to stuff the "The Tribulation"+ "The 1,000 Years"+"The Little Season of Satan's Release" into the 30-70A.D. timeframe preceeding Babylon's Fall will never work alongside the preterist insistence that "time statements" be taken seriously, (not to mention "expectation statements"). This awkward attempt only serves to undercut preterist credibility, leaving us all exposed to the rightful charge of hypocrisy regarding our interpretation principles that deduce the Lord's Accomplished Return in the first place.
BONUS:
I cannot get away from Hebrews 12:22-24 and Hebrews 12:28's description of The Heavenly Jerusalem, (presumably equal to the New Jerusalem), as a reality being received at the time of Hebrews pre-70AD publication date. At any rate, the New Jerusalem's arrival is associated with the beginning of "The Day of the Lord" aka "The 1,000 Years." The New Jerusalem's arrival is also associated with old Jerusalem/Babylon's departure or "Fall." And old Jerusalem/Babylon's Fall is associated with the beginning of "The 1,000 Years" aka "The Day of the Lord," as well. Therefore, the New Jerusalem was arriving as the old Jerusalem was departing as 70A.D. approached, all this as "The Day of the Lord" period of history began.