The only thing I tell you is that the name by which this god is known in Hebrew and always has been is Yeshu. This a name of foreign origin and is not related to any Hebrew name. It is also the name by which the god is known by in India. The origin is plainly Hindi.
The Greek name came in as Iesous. That is a direct transliteration of Yeshu. They added an “s” to every name.
The first time we have evidence that the Jews were even aware of the myth was circa 120 when the book arrived in Greek and Meir, the sage, read it because it was supposed to have been set in Israel. He condemned the book.
What happened outside in the empire I have no idea. But the only time there were known Jewish Christians in Israel was in the period between 120 and 135. In the Bar-Kokhbah War against Rome in which 600,000 people died on both sides, the only group that refused to muster were the Christians. As a result Bar-Kokhba accusing them of cowardice and engaging in espionage formally drummed them out of the Jewish people and they have never been allowed back in.
When the persecutions started immediately after the Jews lost the war, the Christian leaders went to Hadrian and proclaimed, “we are not now nor have we ever been members of the Jewish people.” And he let them go.
To draw such conclusions involves using a very imaginative form of theological interpolations. The word or term 'god' or 'God' is very similar in many of the semitic languages. The Philistines and Hebrews and even Egyptians shared many of the same roots. As in the Hebrew scriptures the God of Israel was known by His Name. What we have specifically later is the tetragrammaton of YHWH (Yehovah, Jehovah) or as the observant Orthodox Jewish render Hashem: The Name. It is from the tetragrammaton of YHWH which Yeshua is derived.
On the matter of anointed the two words the Greek 'christos' and the Hebrew 'mashach' there is no difference is usage. Reference 1 Samuel 16 when David is annointed by Samuel a literal pouring or rubbing of oil was involved. The Hebrew scriptures use 'mashach' for this most important event. David became YHWH's annointed king of Israel. Your etymologies, frankly, do not hold up as there were several dialects of Greek in first century AD (CE) however, Koine was used in recording the gospels and epistles. This is because by the time of Jesus' ministry Greek was clearly the lingua franca of that era. The gospels record that at Jesus' crucifixion Jesus' name was inscribed in Hebrew, Greek and Latin (reference John 19).
But the only time there were known Jewish Christians in Israel was in the period between 120 and 135.
Then you throw out a lot of history with the bath water. Frankly this is late 19th cetury revisionist theory which was refuted in the early 20th Century. For example, in the late 19th Century, the historical accounts recorded in the gospel according to Luke, Acts and the epistles of Paul were thought by even some conservative theologians to be 100-300 year accounts by a shadow author. That was the norm in the critical age of the late 19th century. Until a noted archaeologist named Sir William M. Ramsay decided to strike out and investigate.
William Ramsay was known for his careful attention to New Testament events, particularly the Book of Acts and Pauline Epistles. When he first went to Asia Minor, many of the cities mentioned in Acts had no known location and almost nothing was known of their detailed history or politics. The Acts of the Apostles was the only record and Ramsay, skeptical, fully expected his own research to prove the author of Acts hopelessly inaccurate since no man could possibly know the details of Asia Minor more than a hundred years after the event—this is, when Acts was then supposed to have been written. He therefore set out to put the writer of Acts on trial. He devoted his life to unearthing the ancient cities and documents of Asia Minor. After a lifetime of study, however, he concluded: 'Further study . . . showed that the book could bear the most minute scrutiny as an authority for the facts of the Aegean world, and that it was written with such judgment, skill, art and perception of truth as to be a model of historical statement' (The Bearing of Recent Discovery, p. 85). On page 89 of the same book, Ramsay accounted, 'I set out to look for truth on the borderland where Greece and Asia meet, and found it there [in Acts]. You may press the words of Luke in a degree beyond any other historian's and they stand the keenest scrutiny and the hardest treatment...'
When Ramsay turned his attention to Paul's letters, most of which the critics dismissed as forgeries, he concluded that all thirteen New Testament letters that claimed to have been written by Paul were authentic.( https://archive.org/details/bearingofrecentd00ramsuoft)
To throw out other historical accounts and somehow hold up a standard of "history did not happen if we don't have the original autographs", then Julius Caesar's writings are fable and myth. If you can't produce the original copy of "The Conquest of Gaul" then according to your reasoning it must never been written or frankly never happened.
I believe you are hedging your historical bets on a few already refuted 19th century sources (see Sir Walter Ramsay's piece above) as a foundation of your belief or lack thereof. Doing so is unwise...as building a house on sand. As it was once said and still true today:
“Therefore everyone who hears these words of Mine and acts on them, may be compared to a wise man who built his house on the rock. And the rain fell, and the floods came, and the winds blew and slammed against that house; and yet it did not fall, for it had been founded on the rock. Everyone who hears these words of Mine and does not act on them, will be like a foolish man who built his house on the sand. The rain fell, and the floods came, and the winds blew and slammed against that house; and it fell—and great was its fall.”