I believe most of the things you are saying here, I have already replied to in post:
How are these Great Beings explained?
New thing you are bringing up is why not say everything is symbolic and did not happen. Why choosing some to be symbolic and some literal.
For me, the reason is Bahaullah. I rely on Him. He has fulfilled the prophecies of Bible, Islam, and other religions.
To me He is Manifestation of God, promised in Bible in many ways, such as return of Christ.
His words and teachings are source of wisdom and guidance. He did not go to school and did not have any significant training in religion, history, science, yet whenever they asked Him any question, He wrote a tablet from His mind, without having any books to learn from or get references from. His works are numbered to more than 17000 works, some of them are a whole Book, written in a just a day or two, as witnessed several times. Despite all these, not even a single mistake or error could be proven to exist in His writings.