It is a reasonable request, that answers "do not use the inerrancy doctrine." Your second request is that "the answer does not merely use generalized arguments that target a liberal assertion that most purported fulfilled prophecies are not really prophecies because the record was always written after the fact." But there's a problem of inconsistency here. I refer to the old saying, "What's sauce for the goose is sauce for the gander."
If these post-2000 liberal scholars you refer to have a vested interest in debunking the Christian view that Jesus made that one particular prophecy pre-A.D. 70, that has to be taken into account. Of course, they would never publicly admit to that, should that be true, but claim objective scholasticism is their only concern. Just because those scholars do not have "the inerrancy doctrine" is no reason not to bear in mind the possibility that they are out to disprove this inerrancy doctrine, and what better way to do that than to claim that Jesus never made that particular prophecy - that it was added into the gospel account post-A.D. 70?
This means, then, that if these modern scholars wish to have a level playing-field for this matter, they will acknowledge that the charge of possible bias holds equally good for them as it does for Christians. In other words, nobody should pretend that such possible bias does not exist. That is why this quote from a Christian source (on this very question) holds good:
"Suggested dates for the writing of the Gospel of Matthew range from
as early as A.D. 40 to as late as A.D. 140. This wide range of dates
from scholars indicates the subjective nature of the dating process.
Generally, one will find that the presuppositions of the scholars
greatly influence their dating of the Gospels.
For example, in the past many liberal theologians have argued for a
later dating of many of the New Testament books than is probably
warranted or valid, in an attempt to discredit or cast doubts upon the
content and authenticity of the Gospel accounts. On the other hand,
there are many scholars who look to a much earlier dating of the New
Testament books...
There are scholars who believe the Gospel of Matthew was written as
early as ten to twelve years after the death of Christ... One of the
evidences of this earlier dating of Matthew’s Gospel is that early
church leaders such as Irenaeus, Origen, and Eusebius recorded that
Matthew first wrote his Gospel for Jewish believers while he was still
in Israel. In fact Eusebius (a bishop of Caesarea and known as the
father of church history) reported that Matthew wrote his Gospel
before he left Israel to preach in other lands, which Eusebius says
happened about 12 years after the death of Christ. Some scholars
believe that this would place the writing of Matthew as early as A.D.
40-45 and as late as A.D. 55.
...Had the Gospels been edited before being written down, as some
liberal scholars contend, then it was a very poor job. The writers
left far too many “hard sayings,” and culturally unacceptable and
politically incorrect accounts that would need explaining."
https://www.gotquestions.org/when-Gospels-written.html
Now, this may be the very type of Christian response that you do not want in answers, but I would point out that claims for a pre-A.D. 70 date for the prophecy come from people living shortly after all the New Testament documents had been written, and they had direct access to the earliest copies of them. Iraneus lived circa A.D. 130-200; He was taught by Polycarp of Smyrna who was a disciple of the apostle John. So, there is a direct link right back to one of the apostles who wrote a large percentage of the New Testament.
Origen lived circa A.D. 185-254. Eusebius of Nicomedia was a bishop who spoke at the A.D. 325 Council of Nicaea.
Now we are being asked to consider what non-Christian scholars, post A.D. 2000, say in contradiction to those well-educated men living in an era from less than 100 years after the death of the last gospel author. They did not have mere scraps of gospel manuscript copies in their hands. They knew the chronological pedigree of all these fully-intact documents. Further, if the claim is correct that the gospel accounts were tampered with post A.D. 70, then why were many of Jesus' other "hard sayings" not removed or watered down?
There are some 1,700 years' gap between the earliest recorded supporters of Jesus' making that prophecy pre-A.D. 70. and modern scholars denying it. I would really like to know if this is just an uncomfortable fact that they have given a body-swerve to, in the hopes that nobody else will see its note-worthiness.
Further, Jesus made many other prophecies about world events that would commence from his resurrection from the dead, events that will build up until his spectacular return. It would be nice to think these modern scholars would give every one of them the same examination they've given to Jesus' one about the destruction of Jerusalem, to see if they require the same negativity they've given to that one. Somehow, given that they are unlikely to believe in his resurrection, and consequently not in his sudden re-appearing in the future, that's not going to happen. They must think what they believe, and write what they feel is true, but the case for Christians dissecting their 'discoveries' requires them to first deal openly with the problems raised here.
