A Believer is very wrong about the word NAOS. As a Jew who not only speaks Hebrew, I also speak and read the Greek of the Second Temple period.
The Koine Greek word NAOS means "divine habitation," or "god-house," and not Temple. It is the same word used at Acts 19:24 where the text speaks of the "shrines of Artemis." Depending on the religion the NAOS is speaking of, the word is speaking of the literal sanctuary or room in which a divinty or their presence was said to inhabit. That is why when it is used of YHVH the word means "Temple," but when used of Artemis the word is "shrine."
Luke 23:45 is a prime example of the meaning underlying NAOS when it speaks of the "veil of the NAOS" or Temple being torn. Herod's Temple structures and courtyards actually had many curtains or veils that were used as doors or dividers. Here the expression refers to the veil or curtain "of the NAOS." The inner most chambers of the Temple proper is being discussed here.
The word NAOS comes from the Greek verb, NAIO which means "to dwell." Due to this both Strong's and Thayers agree that the word NAOS means only the proper which houses the Holy and Holy of Holies.
While the individuals speaking with Jesus at John 2:20 state that the Temple had been under construction for 46 years, and it is clear that they are including the construction of the courtyards under the word NAOS, the same Jews are not calling the courtyards NAOS.
To illustrate, when the NAOS fell in 70 CE, much of Herod's other structures like the gates and walls and courtyards remained. But once the main structure fell, the NAOS, the courtyards and remaining walls were no longer called NAOS. Today we still have some of Herod's work, notably the Western Wall, and yet nobody says that since this and other parts of Herod's courtyards still remain that the NAOS is still there. Everyone agrees that the NAOS is gone. Take away the NAOS and the courtyards lose their meaning. The remaining Western Wall is even called the "Wailing Wall" now to demonstrate how we Jews mourn the passing of our NAOS. The space and foundations and much of the stones of Herod's work are still there, meaning the courtyards aren't gone, but the NAOS is.
Revelation 7:15 states that the those of the great crowd "render sacred service day and night in his NAOS." The only place "sacred service" was carried out was by priests serving at the sacrificial altar before the NAOS. The same priests had entry into the Holy and served before the Holy of Holies.
Those in the outer courtyards did not render sacred service. Men who were not priests could go as far as the courtyard where the sacrificial altar was but had no entry into the NAOS as the priests did.
Jewish women had a courtyard further out, and outside of this was a court for the Gentiles. No sacred service could be carried out by those in the outer courtyards, and only priests with entry into the NAOS could render sacred service of any type.
The theology of the Watchtower is that only the anointed can be said to have access to the Holy. It was decorated with cherubim and overlayed with gold, signifying a participation in heavenly life. Thus if the "great crowd" is said to be rendering "sacred service" in the NAOS, it means they have a heavenly calling.
As for the literal sanctuary, the Temple proper, the NAOS, it was originally built quite hastily over the period of a year and a half because the Jews were not quite comfortable with Herod tearing down the one they already had. Once it was done, the rest of the work went at a normal pace, and it would take about 80 years to finish the courtyard structures. Why? Because these structures were not the actual NAOS, and there was no need for haste. People often referred to the entire complex as NAOS, as in the conversation in John 2, but they stopped once the actual NAOS fell in 70.
The fact that "sacred service" is limited to the priestly class who could enter the actual Temple proper or NAOS further demonstrates that this cannot refer to courtyards where others stood. No sacred service could be carried out in them and people restricted to the courtyards could never enter the NAOS.
A Believer, you are mistaken.