You show a massive ignorance of lower textual criticism, history and the canon.
FIRST - the earliest manuscripts are used to translate the Bible. If you buy a UBS Greek New Testament, you will see the notations for every minor difference in those manuscripts. None which affect doctrine. Although it is true that the KJV translators used Erasmus' translations, who was forced by the RCC to use the Latin Vulgate in places, making KJV a translation of a translation of a translation, Bible translators do not do that anymore.
Lower criticism or textual criticism is the science of sorting, comparing the existing manuscripts of ancient documents with a view to reconstructing the text or the original as accurately as possible. For example, the Rylands papryus contains portions of John 8:31-33, 37-38 from 130 AD - barely 40 years after the original was first composed. Another two dozen papryri containing part or all of one or more of the Gospels date from the second, third and fourth centuries and are housed in various museums and libraries throughout the world. The five oldest, most reliable and most complete New Testaments date from the fourth and fifth centuries and all contain the gospels quite well preserved. Nothing to do with translating a translation! Or, become corrupted over the centuries. Instead, going back to the earliest texts, which considering the completeness of them, means there had to be many early manscripts for some to be preserved in such excellent condition, you are parroting internet nonsense about the historical text!
The Bible is the most thoroughly scrutinized book in the history of the world. Every single copyist error is known and recorded. That is why understanding how the text has been preserved is so important.
SECOND - To those who are sadly misinformed as the language of New Testament Israel, it was mostly Aramaic. Mark's gospel uses loan words from the Aramaic within the Greek. When Alexander the Great (from 331-323 BC) conquered the known world, one of his goals was to "Hellenize" the world. That means to not only make Greek the main language, but to spread the Greek culture. And it worked! Everyone adopted Greek as the main language of trade and commerce. The Hebrews lost their language so badly, that a Greek translation of the Hebrew Old Testament, known as the Septuagint (LXX) had to be translated soon after that. A simplified form of Attic (Athenian) Greek developed into what is now called "Hellenistic Greek." By New Testament times, the lingua franca, or common language was koine Greek - or common Greek. Greek became the language of business, commerce and relations with the military and political authorities.
THIRD - As for your firm dating, you have obviously been reading some websites which are spewing out lies to discredit the Bible. Traditional dating for Matthew is the late 50's or early 60's, as indicated in the writings of Irenaeus (c 175) who wrote that Peter and Paul were still alive when this gospel was written. The fact that Matthew uses terms like "field of blood," showed connection with conditions in Palestine, and that this is prior to the devastation in Jerusalem in 70 AD. If it had been written after 70 AD, Matthew certainly wouild have note the prophesy about the destruction of Jerusalem had been fulfilled. That he did not, points strongly towards it being written before that point!
Mark was likely written probably before the Jewish war. It is a pastoral response to stressful times, as Christians were facing the death of eye witnesses which created a need to preserve and stablilize the knowledge of Jesus. Mark compiled a written record of the preaching of Peter and perhaps others to edify the church, and aid it in the task of proclaiming the gospel in the Greco-Roman world.
Luke was likely written around 62 AD. Since Luke and Acts are so closely related, they would have been released about the same time. This date is suggested because Paul's death is not noted in Acts, which is mostly the story of Paul. Luke also notes in both Luke 1 and Acts 1, that he is compiling the stories of the eye witnesses to Jesus, life, miracles, ministry and his death and resurrection.
John, written by the Beloved disciple was the last of the gospels written. He does not rely on materials from the other three synoptic gospels as much, but sets an account of both the events and the incarnational theology of Jesus which he witnessed in his gospel. Early church fathers all agree John wrote his gospel. Dating for this gospel is difficult, with dates ranging from 80 AD and upwards. However, internal evidence points to earlier, as John writes his gospel from a presupposition of Judaism before the war which destroyed Jerusalem. Jesus' conflicts with the Jewish leaders, and his critical dispostion toward the temple suggest that the temple was still operational, or John would have mentioned it as a logical result of the Pharisees and scribes wandering far from God's plan and purpose.
A good book to read on this topic is "Jesus and the Gospels: An Introduction and Survey" by Craig L. Blomberg.
A good link to start with is:
https://carm.org/when-were-gospels-written-and-by-whom
Finally, I find it strange that only a few days ago I addressed this whole issue, although not in as great of depth! It was a different person trying to tear apart the gospels, using some of the same words used by the OP. So an alter? Or random chance? I certainly hope the latter, but it is indeed strange that this topic is being forced down our throats again.
