You mention the second temple was destroyed in 70 AD which is correct, but I am wondering about the temple mentioned in Ezekiel 40-42. Because as far as I can tell that temple has never been built. It isn't similar to any other temple that has been built in the past, so could it be referring to one to be built in the future?
Good question, notice Ezekiel 44 gives the answer...
Ezekiel 44 King James Version (KJV)
1 Then he brought me back the way of the gate of the outward sanctuary which looketh toward the east; and it was shut.
2 Then said the Lord unto me; This gate shall be shut, it shall not be opened, and no man shall enter in by it; because the Lord, the God of Israel, hath entered in by it, therefore it shall be shut.
3 It is for the prince; the prince, he shall sit in it to eat bread before the Lord; he shall enter by the way of the porch of that gate, and shall go out by the way of the same.
Now there is much debate like you say about it, and you also have to look as to what will happen after
as we see in the following verses:
Revelation 3:12
Him that overcometh will I make a pillar in the temple of my God, and he shall go no more out: and I will write upon him the name of my God, and the name of the city of my God, which is new Jerusalem, which cometh down out of heaven from my God: and I will write upon him my new name.
Revelation 21:1-3 King James Version (KJV)
1 And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.
2 And I John saw the holy city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband.
3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God.
Peter confirms what happens to the earth and the heavens above it:
2 Peter 3:10-12 King James Version (KJV)
10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
11 Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
12 Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat?
So we have Herods Temple where we know Christ was, but now look at this...
Exodus 25:8-9 King James Version (KJV)
8 And let them make me a sanctuary; that I may dwell among them.
9 According to all that I shew thee, after the pattern of the tabernacle, and the pattern of all the instruments thereof, even so shall ye make it.
Exodus 25:40 King James Version (KJV)
And look that thou make them after their pattern, which was shewed thee in the mount.
Revelation 15:5 King James Version (KJV)
And after that I looked, and, behold, the temple of the tabernacle of the testimony in heaven was opened:
Revelation 21:3 King James Version (KJV)
And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God.
As for more on the prophecy of the 70 weeks, here is a good explanation: "Prophecies are couched in symbolic language that needs to be unraveled before the meaning of the words can be understood. Prophetic time is used as a symbol to be interpreted in the light of Scripture.
According to the number of the days in which you spied out the land, forty days, for each day you shall bear your guilt one year, namely forty years (Numbers 14:34 NKJV).
I have appointed thee each day for a year (Ezekiel 4:6).
These two texts provide the key—the day-year principle. This principle takes prophetic days and converts them to actual years. Applying this principle to the 70-week prophecy will show that Jesus of Nazareth is the Messiah.
Six Messianic Tasks
Seventy weeks are determined upon thy people and upon thy holy city, to finish the transgression, and to make an end of sins, and to make reconciliation for iniquity, and to bring in everlasting righteousness, and to seal up the vision and prophecy, and to anoint the most Holy (Daniel 9:24).
“Thy people” were God’s chosen people Israel. Seventy weeks resolves into 490 days. Applying the day-year principle, 490 days become 490 years.
The 490 years were appointed to the Jewish nation for these six reasons found in Daniel 9:24:
1. to finish the transgression
2. to make an end of sins
3. to make reconciliation for iniquity
4. to bring in everlasting righteousness
5. to seal up vision and prophecy
6. to anoint the most Holy
These six issues could only be fulfilled in and through the Messiah. Who else could make reconciliation for iniquity or bring in everlasting righteousness?
Jesus Fulfills the Prophecy
Know therefore and understand, that from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times.
And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined.
And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate (Daniel 9:25-27).
The angel gives a breakdown of the 70 weeks as follows:
7 weeks of years for rebuilding of Jerusalem (verse 25)
62 weeks of years to the Messiah (verses 25-26)
1 week of years to the close of the period (verse 27)...
The 2300-day prophecy, of which the 70-week prophecy is a small part, was to begin at the command that effected the restoration of Jerusalem. This command went forth under King Artaxerxes Longimanus in the year 457 BC (Ezra 7:12-13).ii
From this starting point, we can determine all the other time markers of the prophecy. Seven weeks were allotted for the restoration of Jerusalem. True to the prophecy, Jerusalem was rebuilt 49 years after 457 BC, which was 408 BC.
Seven weeks (49 day-years) for the rebuilding of Jerusalem and another threescore and two weeks (62 weeks or 434 day-years) brings us to "the Messiah the Prince." Beginning in 457 BC and applying the day-year principle, we can determine the passing of 483 years from 457 BC which brings us to 27 AD (allowing for the conversion from BC to AD being one extra year).
In 27 AD, Jesus was anointed by the Holy Spirit on the occasion of His baptism which marked the beginning of His ministry (Luke 3:21-23). This baptism marked the event in Daniel’s prophecy “unto the Messiah the Prince.” When Christ proclaimed, “The time is fulfilled” (Mark 1:15), He was referring to this part of the prophecy.iii
The end of the prophecy is 34 AD, 7 day-years after the baptism:
And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and oblation to cease (Daniel 9:27).
Christ would confirm the covenant made with Israel for one prophetic week (7 years), but oblation (offerings) would cease in the middle of the week (3 ½ years after 27 AD). This mid-point brings us to 31 AD—the year Christ was crucified. It was at His death that he put an end to the system of offerings practiced by Israel for so many years. "The 70-Week Prophecy | Daniel 70 Weeks Prophecy ...
https://amazingdiscoveries.org/S-deception_Jesus_70-week_prophecy_Daniel