Though many people interpret the NT expression of "Kingdom of heaven" (including the WT [in regards to Jesus and the 144,000] and Vanderhoven7) as meaning the "kingdom in heaven" years ago I discovered that a number of scholars say it doesn't mean that (and it does not mean that Matthew 8:10-11 says Abraham, Isaac and Jacob will be in heaven instead of on Earth). Those scholars say it means the kingdom which receives its authority from God and thus that the location of the authority is from heaven, with the kingdom on Earth. Some of them also say it was a way to avoid using the name/tile "God" when communicating to Jewish non-Christians (ones who try to avoid over use of the 'name' of God) and that such is why it is used in the gospel called "According to Matthew" (which is claimed to be primarily written to specifically convince Jews) but not in the gospel called "According to Mark" and not in the gospel called "According to Luke" (or only infrequently used in those two books). That was a key insight to me when I doing independent biblical study (that is independent of WT literature) while I was still a Christian. It contributed to me coming to believe that the Church of God (Abrahamic Faith) and the Church of God (Sevenh Day) are the two religions of Christianity which are the closest to biblical Christianity.
Keep in mind that Daniel 2:44 says the kingdom will be on Earth, ruling from Earth (though with it being brought into existence form a source located in heaven, namely from YHWH God).
Note that in the Lord's prayer (also called the our father prayer) the book called "According to Matthew" attributed Jesus as telling his apostles/disciples to pray that the father's will be done on Earth as it is in heaven. This is consistent with the idea of expecting the kingdom to eventually extend to Earth, with the Messiah ruling on Earth.
For example, see https://en.wikipedia.org/wiki/Kingdom_of_heaven_(Gospel_of_Matthew) . It says the following.
'Kingdom of heaven (Greek: βασιλεία τῶν οὐρανῶν) is a phrase used in the Gospel of Matthew. It is generally seen as equivalent to the phrase "kingdom of God" (Greek: βασιλεία τοῦ θεοῦ) in the Gospel of Mark and the Gospel of Luke. ... Classical scholar Howard W. Clarke notes that Matthew 3:2 is the first of twenty-nine references to the "kingdom of heaven" in the Gospel of Matthew.[2] The gospels of Luke and Mark tend to prefer the term "kingdom of God". Matthew's use of the word "heaven" is often seen as a reflection of the sensibilities of the Jewish audience this gospel was directed to, and thus tried to avoid the word "God." Most scholars feel the two phrases are theologically identical.'
https://www.newworldencyclopedia.org/entry/Kingdom_of_God says the following.
'In the synoptic Gospels (which were written in Greek), Mark and Luke use the Greek term "Basileia tou Theou," commonly translated in English as "Kingdom of God," while Matthew prefers the Greek term "Basileia tōn Ouranōn" (Βασιλεία τῶν Ουρανῶν) which has been translated as "Kingdom of Heaven." Biblical scholars speculate that the Matthean text adopted the Greek word for "heaven" instead of the Greek word for "God" because—unlike Mark and Luke—it was written by a Jew for a Jewish audience so, in keeping with their custom, avoided using God's name as an act of piety. In Matthew, "heaven" stands for "God." The basis for these terms being equivalent is found in the apocalyptic literature of Daniel 2:44 where "the 'God of heaven' will set up a 'kingdom' which will never be destroyed."
... Jesus assumes his audience understands the Kingdom foundation that was laid in the Hebrew Scriptures. When he speaks of the Kingdom of God/Kingdom of Heaven (both meaning the same thing) he speaks of the time of the fulfillment of the Abrahamic and Davidic covenants. A time of a restored earth where the faithful will worship and serve their God forever under the rulership of a righteous leader of the Davidic line. This was the Messianic hope of the prophets of the Hebrew Scriptures and was carried over and echoed in the words of John the Baptist, Jesus, Peter, Paul and others in the Greek Scriptures.
Jesus would attach the theme of the gospel message itself with this Kingdom idea. Luke 4:43 tells the reader that Jesus' very purpose for being sent was to "preach the gospel about the Kingdom." He then would send out his disciples to speak this message even before they understood anything about his death and resurrection. Compare Luke 9:1-6, Matthew 9:35, Matthew 10:7, Matthew 16:21-23, etc. The initial seed that must be sown in the hearts of men was also identified as the word of the Kingdom by Jesus in Matthew 13:19. Shorthand for the word of the kingdom was given in Mark and Luke's version of the parable of the sower as "the word" (Mark 4:14) and "the word of God" (Luke 8:11).
Jesus often spoke of the Kingdom of God as the destination for the righteous in the end of days.[18] Jesus' words in the Sermon on the Mount shows that those who follow the "beatitudes" are rewarded with the Kingdom of God/inheriting the earth/comfort etc. Matthew 19 gives an account of Jesus equating popular terms such as "eternal life" and "saved" as the same thing as entering the Kingdom of God when it is established upon the earth. Jesus even taught his disciples to pray: "Let Your kingdom come, let Your will be done on earth as it is in heaven." '