There's a lot that's only mysterious if you need Jesus to be the messiah. If the then-publicly known details of his life didn't line up with him being the messiah despite his followers really wanting him to be, a lot of the Gospel narrative starts to make sense as a bunch of "Here's how he can STILL be the messiah" dot connecting and outright retcons. A made-up conspiracy by the Jews would have been an easy explanation for why his mission appeared to fail, before the "Uh, he meant to do that. He died for our sins." narrative took shape.
A lot of Jesus' story makes sense when you look at it for what it is- a political movement in a very polarized region of the world.
Let's refocus.
Judea, 1st century CE. Rome occupies, but retains local Judean authorities in a puppet state kind of deal.
King Herod is nominally King of Judea ("King of the Jews") and the High Priesthood in the Temple in Jerusalem have Jewish religious authority. But both Herod and the Priesthood's authority is dependent on towing the party line for the Romans.
Though the Judean monarchy and High Priesthood predates Rome by thousands of years they have essentially become collaborators in Roman occupation.
Enter Yosef ben Yoshua, aka Jesus. A carpenter-turned-rabbi who is also supposedly descended from the royal house of David on his mother's side.
Jesus doesn't outright attack his distant cousin Herod or the Priesthood but his egalitarian form of Judaism, where one can have a personal connection to G-d without having to go through the monarchy or Priesthood, is very popular among Judeans who are upset at their own government for collaborating with Roman occupiers.
A movement springs up where Jesus' more zealous followers start calling him "King," a reference to his connections to the royal family and a not so secret implication that maybe Herod's collaborating ass should be tossed out and Jesus made King of Judea.
To the Romans this is a problem. Their occupation has split Judea along multiple lines, with some people willing to work with them and others openly revolting. Jesus represents someone who is not only attacking the authority of their collaborationist regime, but some of his followers have begun talking about open rebellion in his name. Judea is on a knife's edge and Rome decides Jesus needs to die.
Pilate, the Roman governor, tries to pass responsibility off on Herod, as Jesus is a Jew and thus falls under Herod's jurisdiction. Herod asks his cousin if he can perform some of the miracles his followers claim he's performed, Jesus refuses. Herod, very annoyed, decides he's got enough crap to deal with and sends Jesus back to Pilate.
Pilate now has an order from Rome to kill Jesus but Herod won't do it for him, so he just decides to say "hug it" and sentences Jesus to death in the name of Caesar. Roman soldiers mock Jesus and his followers with a crown of thorns and the mocking title "King of the Jews" to belittle the rebellious agitation happening around Jesus.
Then later Christians decide it's all the Jews' fault actually as part of a wider Christian movement to detach itself from Judaism and appeal to some of the very people responsible for Jesus' execution.