Josephus and the Bible agree as to the fact that the seventy years ran from the Fall of Jerusalem until the Return. Certainly. Nebuchadnezzer took Jewish captives in his 23 rd year but these were not from Judah. Judah was completely destroyed and desolated in the 18th regnal year of Nebuchanezzer which is exactly what the Bible writers depicted.
Josephus does not connect the last deportation with the seventy years as you claim because those Jews were not in Judah at that time but elesewhere. Josephus nowhere begins the seventy years from any other event excepting from the destruction of Judah, Jerusalem and the Temple. Your claim are simply mistaken and misleading so just stick to the facts.
Jeremiah 44:14, 28 clearly show that those who "escaped from the sword" who had run down to Egypt were to return to Judea:
Jer 44:14 "And there will come to be no escapee or survivor for the remnant of Judah who are entering in to reside there as aliens, in
the land of Egypt, even to return to the land of Judah to which they are lifting up their soul[ful desire] to return in order to dwell; for they will not return, except some escaped ones.'"
JER 44:28 "And as for the ones escaping from the sword, they will return from the land of Egypt to the land of Judah, few in number; and all those of the remnant of Judah, who are coming into the land of Egypt to reside there as aliens, will certainly know whose word comes true, that from me or that from them."'
These two verses contradict what you are claiming. In order for your view to work, Judah had to be completely desolated after the destruction of Jerusalem. That doesn't work if they return in the 23rd year, which is precisely what occurred. Where, exactly, do these deported in the 23rd year come from?
If they come from Egypt there's a problem since it is clear that there is the potential of them re-entering Judea, meaning it was not completely desolated with no one passing through. Now, Josephus specifically claims those deported in year 23 WERE from EGYPT.
From the above we can establish that there were no other Jews to deport other than those remaining from the sword in Egypt. Your view only
works if it is presumed there were Jews scattered all about outside Judea who were then rounded up and deported in year 23. There is
an attempt to associate those who were scattered about with those who had fled Judea when Jerusalem was destroyed. But these ALL
returned during the governorship of Gedaliah, leaving no significant numbers of Jews, therefore, to deport.
JER. 40:11 And all the Jews that were in Mo´ab and among the sons of Am´mon and in E´dom and those who were in all the [other] lands,
they also heard that the king of Babylon had given a remnant to Judah and that he had commissioned over them Ged·a·li´ah the son of
A·hi´kam the son of Sha´phan. 12 And ALL the Jews began to return from ALL the places to which they had been dispersed, and they kept
coming into the land of Judah to Ged·a·li´ah at Miz´pah. And they went gathering wine and summer fruits in very great quantity.
Based on the above, therefore, there were no significant numbers of Jews in the surrounding areas anymore. They had all returned to Judea and become a composite remnant of people again. After Gedeliah was killed this remnant fled to Egypt and refused to return at
Jeremiah's urging. So Nebuchadnezzar came into Egypt in year 23 and killed off the majority of those people and a few "remaining from
the sword" on their way to Babylon stopped in Judea.