Any garauntee in the constitution is meaningless since the judiciary in China is not allowed to use it as a way to invalidate law. The party itself gets to decide whether they are following the constitution or not, imagine if Trump could make his executive orders without worrying about federal judges throwing them out.
Heck even the party has had issues with the judiciary at lower levels (things that didn't involve the party) where they found judges with limited education making strange decisions based on flawed logic, and of course low level corruption.
While I'm sure they don't have any intention of making the judiciary independent, there were signs that even party members were a bit dismayed by some of the decisions if only because they were worried about public perception. I belive they talked about launching some educational efforts.
Judges aren’t really that prestigious in China because they are dwarfed in power and influence by officials, so as a result it doesn’t attract the best people.
