“But ye are come unto mount Sion, and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels, To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,” (Hebrews 12:22–23)
Try reading the whole chapter. It does not say what you are claiming.
Notice it says the church is written in heaven, not present in heaven.
God will live with us in the new Jerusalem in eternity, but he is not there yet.
Hebrews is written to the Jews, not gentiles.
Hebrews 1 New International Version (NIV)
God’s Final Word: His Son
1 In the past God spoke to our ancestors through the prophets at many times and in various ways, 2 but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom also he made the universe. 3 The Son is the radiance of God’s glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven. 4 So he became as much superior to the angels as the name he has inherited is superior to theirs.
Side note here, it says he set down at the right hand of the father on the throne of God.
That could not have been in the New Jerusalem because the new Jerusalem was not prepared until Christ ascended. Yet the throne of God is mentioned many times before the resurrection.
Hebrews has a lot of prophecy in it.