It is 70 x 7 weeks (heptads). 70 x 7 weeks of years.
The 7 years of
Daniel 9:27 is the same seven years following the Gog/Magog event in Ezekiel 39.
In the first year of Darius I Daniel understood by the book the number of the years,
whereof the word of the Lord came to Jeremiah the prophet,
that He would accomplish 70 years in the desolations of Jerusalem.
Daniel 9:1-2
And Daniel continued even unto the first year of king Cyrus.
Daniel 1:21
Now in the first year of Cyrus king of Persia,
that the word of the Lord spoken by Jeremiah might be accomplished,
the Lord stirred up the spirit of Cyrus king of Persia....
and he has charged me to build him a house in Jerusalem....
2 Chronicles 36:22-23
Daniel was in Babylon the full seventy years; the Babylonian captivity.
In Daniel 9:1-2 (above) Daniel is reaching close to the end of those seventy years.
And reading Jeremiah he understands the seventy year time frame.
Jeremiah said that after seventy years many nations would be punished
beginning with Jerusalem; Jeremiah 25:12,18,26.
Then I took the cup at the Lord's hand,
and made all the nations to drink,
unto whom the Lord had sent me.
To wit, Jerusalem, and the cities of Judah,
and the kings thereof, to make them a desolation,
an astonishment, an hissing, and a curse, as it is this day
Jeremiah 25:18
Having read that, Daniel starts to pray about it.
And I prayed unto the Lord my God, and made my confession,
and said, O Lord, the great and dreadful God,
keeping the covenant of mercy to them that love Him,
and to them that keep His commandments.....
O Lord, according to all thy righteousness,
I beseech thee, let thine anger and thy fury
be turned away from thy city Jerusalem,
thy holy mountain: because of our sins,
and for the iniquities of our fathers,
Jerusalem and thy people are become a reproach
to all that are about us.
Daniel 9:4,16
It is clear that Daniel understands that Jeremiah 25:12-26 was happening, that is what the text says.
He does not know how it ends for him, we know due to 2 Chronicles (above)
it is specifically stated that what Jeremiah said was fulfilled during the reign of Cyrus,
those initial seventy years ended at that time.
And that is the context of Daniel 9:24.
In chapter 8 Gabriel comes and gives Daniel specific details about the vision
Daniel saw in chapter 8, Gabriel goes over each animal specifically.
Chapter 9 begins with Daniel reading Jeremiah,
understanding that he is in a seventy year captivity, and praying about it.
Gabriel comes and gives Daniel more information about the time frame.
Some translations use the word "sevens" some "weeks".
I hope to have established very clearly above with scripture
that the context is the seventy year captivity Daniel was in.
And so it makes perfect sense that what Gabriel tells Daniel
is that seventy such Captivities would happen.
Seventy captivities are determined upon thy people and upon thy holy city....
Daniel 9:24
Notice that is directly in relation to Daniel's prayer and to the captivity he is in.
And we can see multiple 70 year periods of captivity for Israel.
The Babylonian captivity, and the 0 - 70 a.d. captivity.
And so in Daniel 9 we are told about 4,900 years worth of captivity,
seventy 70 year periods of time, starting in Daniel's time,
and also with the Messiah as a key point within the time frame.
Know therefore and understand, that from the going forth of
the commandment to restore and to build Jerusalem unto the Messiah the Prince [Ezra 4:24, Haggai 1:1-8]
shall be seven captivities and 62 weeks:
the street shall be built again, and the wall, even in troublesome times.
And after the 62 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 until the end of the war desolations are determined.
Daniel 9:25-26
That is how I think it should be understood,
now that I write it all out, in that passage it is seven captivities and 62 weeks,
but the overarching timeline is seventy captivities.
Darius [Haggai 1:1] died 486 BC.
BC counts backwards to the birth of Christ.
King Herod died around 4 BC.
Therefore it was about 490 years after Haggai
and then another 62 weeks that the Messiah suffered the death penalty.
Daniel 9:24-27 is telling us about 4,900 total years,
and so after the Messiah there would still be thousands of years.
And ok, so 4900 minus 490 is 4410 years.
So about 4410 years would remain after the Messiah.
1290 stated in Daniel 12:11 plus 1335 stated in Daniel 12:12 is 2625.
I think both of those should be understood as years and not days.
I'm uncertain how we get 1260 specifically.
But adding 1260 + 1290 + 1335 we get 3885.
As years, that is only a 525 discrepancy from the needed 4410.
-------
The texts of Ezekiel 37-39 and Revelation 20 give a clear and matching timeline.
Ezekiel 37:1-14 = Resurrections.
{ see also Acts 23:5-8, 26:6-8,
Ezekiel 37:12 is the promise of resurrection made to the fathers collectively that Paul speaks of in Acts }
Ezekiel 37:15-28 = Reign. { Jeremiah 30:9 an actual resurrected David }
Ezekiel 38 and 39 = Gog and Magog.
Revelation 20:4-5 = Resurrections.
Revelation 20:5-7 = Reign.
Revelation 20:7-10 = Gog and Magog.
Both texts are speaking about the same events in different ways,
giving different details of events that are yet to happen.
The Messiah also expounded on Ezekiel's prophecy.
There are only two accounts in the whole Bible that use the phrase "from the four winds"
they both are speaking about actual resurrection, the same event.
"Come, from the four winds, Oh breath of life,
and breath upon these slain that they may live,
....and they stood upon their feet an exceedingly great army"
Ezekiel 37:9-10
"He shall send forth His angels with the great sound of a trumpet
and they shall gather together His chosen ones, from the four winds"
Matthew 24:31
The Lord returns gloriously, resurrecting Israel from death, David and all righteous of Israel and the saints,
will be resurrected in a moment to be an exceedingly great army with the Lord in the air.
And we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air.
And such is the great restoration of Israel, the Lord restores from even death
and brings His people very gloriously back into their land.
As such the talk will be of that glorious return and no more of the red sea and Exodus.
For 1000 years Satan will be locked away.
After 1000 years he is let loose one last time and will go out to deceive,
and gather the nations, Gog and Magog, and gather them for battle against the saints.
But a fire will come down and devour them all, and kindle the world itself ablaze.