If the historical Jesus and the historical Yahweh were mundane and carnal, then how can a personal experience of Jesus or God make sense?
It would not make any sense.
This is a very difficult and controversial subject when seen in it's true light.
What can be seen from even a casual study like you present is that Christianity has not only changed but has become completely severed from its roots.
The changes that have occurred have rendered it vain and useless.
If the historical Jesus is not God then the whole thing comes tumbling down.
Once one begins to see that the story of the prodigal son was replaced with the historical god-man Jesus, you can begin to see the enormity of the problem.
The scriptures were written so that mankind would not lose the knowledge of how to return to the kingdom of heaven from where we came.
Jesus could have been any man.
He was a prodigal son just like us.
He just happened to be the first to overcome and return to the Father.
He liberated us from the mystery religions and the need for a teacher by becoming the pattern for us all, just like the entire book of Hebrews proclaims.
Jesus was like you and i, our brother.
This is the reason that it is impossible to find the historical Jesus.
The scriptures, in the pattern of humility, did not ever portray Jesus as God.
His life had to diminish so that the pattern could emerge.
He is not God, he became one with God.
There is a big difference.
The historical Jesus had to die to himself just like we are told to do.
He said to call no one teacher.
The true prophet is within.
The Logos, the son of God is to be found through a search within not without.
He cannot be found outside of ourselves.
Christianity has indeed changed.
Mankind has been robbed of the understanding necessary to return home.
It has been replaced with the jesus-god.