As I said, parables are a teaching tool. Jesus once said to Nicodemus that if you can't understand earthly things, how can you understand heavenly things? We crawl before baby steps, and baby steps before walk, and walk before run. Yes, there're multiple layers of meanings, one theory suggests that the seven kingdom parables in Matt. 13, starting with the Sower, corresponding to the seven churches in Rev. 2-3. It draws a timeline of the spiritual status of the Church throughout the entire church age from the Pentecost to the rapture. But still, we peel it one layer at the time.
The same applies to the old testament without parables Christ our teacher the Holy Spirit spoke not .
How are we to rightly didvde them?