Jesus didn’t task his followers with providing historical evidence. Jesus, throughout the Gospels, constantly praised and rewarded people who had faith. In some cases they weren’t even Jewish people, they didn’t have a clue about the Jewish Messiah, they certainly had no proof that he was anything other than some carpenter’s son from Galilee, they just heard there was a teacher (Jesus) who was curing people and they had faith he could cure them or their loved ones.
He didn’t convince them by offering historical proof. They just believed.
Faith is a gift of the Holy Spirit. We cannot put faith in people’s heads. I find the historical arguments interesting - most educated Christian people do think it’s neat when somebody finds an old piece of archaeology that confirms something in the Bible - but we do not rely on those things in order to believe in it, nor do we “spread the Gospel” by obtaining historical proof of it to show people. The original Apostles didn’t do that and we don’t do that. It’s ultimately going to come down to faith anyway because I have met many atheist or agnostic scholars who are familiar with historical proof and will agree with me that Jesus existed and certain major events in his life took place, but will not agree with me that he was the Messiah or the Son of God because there is no way to historically prove those things.
Also, somehow despite this lack of historical proof, we have billions of people who believe in Jesus because they have faith. Historical proof is obviously not needed for a person to believe.
So with all due respect, your contention that we have to prove the Bible in order to spread it is not correct.