I’m sure Bruce can speak for himself, but I do have a few thoughts and questions. First, you seem to assert that the New Jerusalem is located “just above the earth in the universal heavens” and represents rule “through Israel out to the nations of the world.”
However, Revelation 21:2 explicitly says John saw the holy city “coming down out of heaven from God, prepared as a bride adorned for her husband.” Verse 3 follows immediately with, “The tabernacle of God is with men, and He will dwell with them.” Scripture presents the New Jerusalem as the final union of heaven and earth, not a satellite city suspended in the sky ruling over a distinct earth below.
I also think you may have a misinterpretation of the 144,000 as “144 Cubits.” You said the 144,000 priests are “symbolically described as 144 cubits… a unit of measurement” in Revelation 21.
This is a conflation of two distinct details. The 144,000 in Revelation 7:4 and 14:1–3 refers to people redeemed from the earth (or the sealed of the tribes of Israel). The 144 cubits in Revelation 21:17 refers strictly to the thickness or height of the city wall: “And he measured its wall, one hundred and forty-four cubits, according to the measure of a man.” Equating a structural wall measurement directly to a group of 144,000 human priests forces an allegorical connection that the text does not make.
Then you present an extreme structural division where the Apostles are Kings, the 144,000 are Priests representing ethnic Israel, and “the nations” are passive subjects outside or under this structure. The New Covenant explicitly unifies Jewish and Gentile believers into one body. In 1 Peter 2:9, the entire Church (Jew and Gentile) is called “a royal priesthood, a holy nation.”
In Revelation 1:6 and 5:10, Christ has made all believers across “every tribe and tongue and people and nation” to be “kings and priests unto God.” The New Jerusalem features 12 gates (named for the 12 tribes of Israel) and 12 foundations (named for the 12 apostles), showing that the Old and New Covenant people of God are unified into one single Bride (Rev. 21:9–12), rather than separated into distinct tiers of authority. In the climax of Revelation, all redeemed servants see His face, reign with Him, and function as His priesthood in a fully renewed creation where God dwells directly among humanity.
Be blessed, be a blessing, Jesus is LORD!
Peter