Having corrupt cops in a Chinese series is no problem at all, as long as they're the bad guys and are defeated by the heroes in the end, or at least have a redemption arc.

Here's a Zhihu question where someone asked to be recommended anti-corruption series, maybe you should watch some of the shows mentioned in the replies before concluding that only dull stories can be produced: https://www.zhihu.com/question/502243280