Hi all, Yes
Would Jesus have had to sacrifice His life regardless even if He had been accepted as the Promised Messiah by the Jews?
I could see an alternate history novel being written about that; sort of like a Christian version of a Harry Turtledove story. I actually came up with this idea a while back.
In my idea for a novel, Caiaphas becomes embroiled in a major scandal and steps down as high priest; his successor is younger and far more sympathetic to the teachings of Jesus, becoming (as Nicodemus was) a secret disciple.
Meanwhile, Judas becomes disillusioned with Jesus as before (because Judas wants a political messiah who will overthrow the Romans). He decides to kill Jesus and proclaim himself the Messiah, and attempts to get the new high priest to support him but is rebuffed. So, instead, he ends up gathering a small army of extremists who plan to launch an extremely violent revolt to establish a millennial reign; his army is almost a first-century version of ISIS. However, most of the Jews side with Jesus' peaceful teachings rather than Judas' violent ones.
Judas fails in his attempt to kill Jesus, and the Romans crush his revolt before he can overthrow them. The Romans end up launching a major persecution of the Jews, blaming them all for Judas' uprising even though most of them didn't support it. The Romans even crucify Jesus (with the same "King Of The Jews" plaque), citing his "ties to" Judas, despite the fact that Judas wanted to kill him. In response, the Jews coalesce around Jesus' teachings and the former Jewish priests (including the high priest) become the first Christian priests. Jesus resurrects, confirming their belief that he is the messiah, he gives them instructions on how to survive as a Church and then he ascends.
The Roman Empire becomes very strongly anti-Christian/anti-Semitic around this time. The Jewish Christians, following Jesus' teaching that the Gospel is for everyone and not just ethnic Israel, begin evangelizing various nations outside
the Roman Empire, in places like Africa, India, and China. These locations (along with the Holy Land itself) become the centers of Christianity in this timeline (in which Judaism does not exist as a separate religion from Christianity, since the Jews accepted Jesus).
The point of this story would be to show that God's providence is not adversely affected by human free will, and even if people had made different decisions, His love could still have shown through.