No, I was just quoting from Isaiah there. That's Isaiah speaking many years before Jesus, describing and requiring the Christ to be a Suffering Servant.
Not many ancient historians would contest that Jesus was a historical person, or have any reason to question that he died the way he did. Nor would they contest the public life of John the Baptist or Pilate or Herod for that matter, or that the New Testament documents contain eye witness testimony, as well as incidental historical detail in the form of taken-for-granted shared understanding of historical events in the minds of those who were then alive and able to contest and examine the facts. Many of those who witnessed to Jesus suffered for their convictions, and faced tremendous pressure and incentive to quit.
"And you have to ignore or gloss over the parts that does not fit: 'He was oppressed and afflicted, yet he did not open his mouth.'"
Have you read the remarkable account of Jesus before Pilate?
At the end of the day, you must decide for yourself.
You are correct most historians assume a historical Jesus did exist. Just as they assume Mohammad and Gautama Buddha existed.
If we extract the "factual" statements about the figure in the prophecy, you will see it does not match what we know about Jesus. All the matches are theological construction after the fact to make the pieces fit. And you have to ignore or gloss over the parts that does not fit: "He was oppressed and afflicted, yet he did not open his mouth".