

The repetition is there because these are primarily oral tales that have been barely edited into something that almost, but not quite, has a coherent narrative.
The tales within Journey to the West come from a very wide period of historical storytelling and are in a wide variety of storytelling traditions. There’s very little consistency from tale to tale, and any overarching theme was added much later in forming the “novel”. (It’s a “novel” in the same way that Ray Bradbury’s The Martian Chronicles is a novel, right down to inconsistencies from member story to story.)
Yeah, talk to the hand, you putrid asshole.
Buh-bye.