That all falls down because Jesus doesn't qualify as a messiah.
If there was an historical Jesus, very little can be said about him. He may have been a bit player in the Jerusalem religion industry, he may have preached the imminence of the endtimes like JtB, he may have been executed by the state. Or not. But if he was there, he certainly flew under the radar, entirely unnoticed in life or death at the time. Why any citizen of Jerusalem would even notice him, bother to think about him, let alone think he was a messiah, a leader of any kind, is wholly opaque; the first and most important gospel account of him, Mark's, is devised 45 years after his purported death, and can be mapped episodically onto the Tanakh (and as Ted Weeden points out, the trial of Jesus is taken from Josephus' account (Wars 6.5) of the trial of Jesus son of Ananias / Ananus) ─ although it can't be mapped onto the known history of Jerusalem / Judea around 30 CE. Add to that the not fewer than five Jesuses that the NT offers and while it's clear the gospel writers are making things up to suit themselves, it's far from clear that any of them is touching on real history at any point at all.
You are certainly right about a lot of things.
In the beginning both Jesus and John the Baptist were quite famous.
But as their message began to sink in they became less famous
Until in that last journey to Jerusalem it says, quite candidly in Matt 21,
the city was stirred to ask "who is this?"
In short, they didn't want to know.
If you want to see how studiously the Jews ignored Jesus just read
Josephus. The verses about Jesus being an honorable man and killed
are evidently fake because this "description" would have invited a lot
more inspection. Josephus was an historian - but he ignored a very
famous man who spawned a whole new faith. That's deliberate,
regardless of whether Jesus was just a man or the Son of God.
As for Mark being the first - maybe, that's the popular theory. We don't
know. But as for 45 years....no. That would be, what, ca AD 80?
Paul wrote about Jesus and the resurrection ca AD 50
and Luke wrote his Gospel and Acts before he died ca AD 68.
And we can be sure there was a lot more text flying around the Middle
East before these earliest surviving examples.