Generations of Christians went by before the idea of the Trinity was created. In much of the Bible, Jesus is treated as separate from God, but in some places, Jesus is more identified with God. The Trinity is an attempt to unify the different perspectives as one, but is not clearly spelled out in the Bible. The Biblical authors were writing from different perspectives and had different takes on Jesus.
Luke doesn’t see Jesus’s death as a sacrifice so God will forgive humans for their sins, but rather a key example of how sinful humans are–they killed God’s prophet! If you want to be forgiven, you have to turn back to God, but don’t need a sacrifice, according to Luke.
The Bible doesn’t take a position on abortion. Where it talks about the accidental killing of a fetus, it does so suggesting the fetus is property rather than having the value of a human life.
A version of Christian nationalism believes that Christianity is a pro-war religion that supports strong nationalist policies that protect Christianity and what it views as traditional life. It is more focused on defeating the enemy than on love. It is more about militaristic and capitalist ideology, than the words of Jesus in the Bible.
Why were the gospels so late? Most early Christians could not write. Some thought that Jesus was coming back very soon, so didn’t see the need to write this down.