The LORD gives Israel a standard period of 70 years to get right with Him, but He has liberty to even extend it by few years because of Mercy and Grace if He deems it according to His Perfect Plan, Perfect Will and Perfect Timing. The Great Tribulation period is not "Cast in Stone", remember The LORD said that He can shorten it for the sake of the Elect. Only Him knows what He will do; for Nobody knows the day or the hour except The LORD. We are currently in Birth Pains, but not The Great Tribulation Period. The Rapture happens before the onset of The Great Tribulation period. The Great Tribulation Period is part of The LORD’s Love, Mercy and Grace for the Jews (Israelites).
-In other words, any moment after Daniel’s 70th year strikes (hits), The Messiah Jesus Christ will be coming to Jerusalem (Israel) to establish His millennium reign on the earth (The Second Coming of The Messiah Jesus Christ). Meaning that the Messiah Jesus Christ essentially cannot come to establish His reign in Jerusalem, Israel any time within the 69 years after the command has been given to reestablish and rebuild Jerusalem (which started with the re-establishment of the modern state of Israel in 1948). But He can then come (to Jerusalem, Israel) any moment once the 70th year is reached; either on the 70th Year or Later on according to His Perfect Will. But then, only The LORD then knows the day or the hour of the second coming of The Messiah Jesus Christ to establish His millennium reign on the earth (while based in Jerusalem, Israel). All this is very powerfully captured and hinted in the book of Daniel 9: 24-25 which states as follows: ‘“Seventy weeks are determined For your people and for your holy city, To finish the transgression, To make an end of sins, To make reconciliation for iniquity, To bring in everlasting righteousness, To seal up vision and prophecy, And to anoint the Most Holy. “Know therefore and understand, That from the going forth of the command To restore and build Jerusalem Until Messiah the Prince, There shall be seven weeks and sixty-two weeks; The street shall be built again, and the wall, Even in troublesome times.”’