That is not entirely true. The central committee is extremely powerful, but so are the local governments that actually send the representative, the reason the central committee always votes in unanimity is because the discussion happen at the local government level, a local Chinese government may be ruling over hundreds of millions of people.

I'm not saying this is good, I'm merely stating that the central committee power and Xi's power is still limited by the sheer size of the Chinese state. If you compare that dictatorship to the Stalin dictatorship or Gheddafi dictatorship you'll find that Xi does not have that kind of unfettered power through sheer violence, he still needs to make a high number of cogs to work in unison to exercise it.