Q. The temple mount is no more but the Lord is to go through the golden gate? and is not the New Jerusalem to come to the new Earth?
A. The Lord will enter the East (Golden) Gate of the Millennial Temple (Ezekiel 44:1-2) which will not be located on the current Temple Mount. If you plot the location given in Ezekiel 48:10 on a map you’ll see it’s where the ancient city of Shiloh once stood.
The New Jerusalem at 1400 miles square and 1400 miles tall is about 1/6th the size of Earth. It would not fit in Israel, and if it was located on Earth it would cover most of Europe and be over 4000 times as tall as the world’s tallest building. The Bible only says that it comes down from heaven, not that it lands on Earth.