I say Luke. Matthew is similar to Luke and more entertaining, but I feel it’s kess accurate. Mark doesn’t go into details too much, but it’s the only one that suggested that Jesus survived his crucification by passing out from blood loss. As for John, the only part of that book I liked was “The Word”.
Mark was probably written first and may have fewer editorial additions. Matthew changes Mark's account in a few places. Luke was aimed at Gentiles and may have changed some of the more "Jewish" references. John is considered the least accurate by true bible scholars. My favorite is Matthew only because it includes the Sermon on the Mount. I have a hard time understanding the Gospel of Thomas.
I like the one where Jesus just tells people to be nice to the poor and love one another and basically teaches people how to not be selfish twats, and doesnt get too deep into the supernatural stuff or the "I am the way to heaven" stuff. Which one is that? And I like when Jesus walks into the market like a bad ass and overturns the tables of the money changers. Like a boss, Jesus .
Matthew, Mark, Luke and John. All are important, relating to what Jesus did and accomplished while here on earth. I have read all 4 in succession many times. A great way to grasp the mental disposition of Jesus and learn from the illustrations that he used while teaching.
I somewhat doubt that any of the disciples had the literary capacity to write the testaments. While I am not suggesting that they are fake, the method and depth of description of events would have been down to the scribes who documented them. I also wonder whether the authors of the bible edited them to remove duplication.
That’s why it’s called faith. It’s not a science or history book. Much of one’s belief in the Bible comes through faith.