I see dictatorship as monarchy in disguise. China's leadership as observed are not passed down within a singular family or families and the succession of which have not observed militarial coup. If the dictator can't have his/hers own blood-heir to take over, where is the dicatorship in this?
Then we can’t know if a country was a dictatorship ship until a ruler dies. Also, all countries with despots ousted and replaced by others, disqualifies as dictatorships.
I don’t like your definition. I’d rather look for rule of law and signs of democracy. Both of which are very scarce in China.
Many of those despots have every intent and actions that we have observed to have their heirs assume office, only that it was stopped. It's about that they have that power in their form of government where they make all the calls, not them actually achiving it.
On the other hand, many of Xi's predecessors are well-alive, well, two of them, if they are/were dicators, what is Xi? There are three dictators at different times in China, with one in the office and the other two well and alive? I doubt dictatorship would be an accurate account for what's really going on.