Why did bach want to be a composer?

There is no evidence to suggest that Bach ever wanted to be a composer. There is no record of Bach ever expressing any such desire, and he never wrote about it in his personal writings or correspondence. In fact, Bach's primary occupation was as a church musician, and he only composed music when he was commissioned to do so. It is more likely that Bach became a composer because he was naturally gifted in music and it was the most direct path to a successful career.