Just something coming into my mind given all the recent 'new hate speech laws' and seeing the slow growth of resistance to all these decrees.
We've seen all these policies but EVERY ONE of them is a failure due to spotty enforcement (even if by design), negligence, inefficient allocation of resources, extremely poor supervision etc.
Yet we can see in other countries, despite different issues plaguing them, they are able to have authoritarian rule like in China with their social credit score and the like.
Is the main reason why the left is slowly losing every gain they make or attempts to copy authoritarian rule similar to others down to simple lack of basic competency? As I think a lot of people would be ok submitting if they knew that the system was actually ran well.
To answer the title, No. You can have competent or incompetent tyrannical dictators/benevolent leaders so competence doesn't really matter for if they are one or the other.
For the actual thought on the other hand humans can take quite a bit of a beating if they have their basic needs guaranteed to them.
However running a system well doesn't mean that the result of said system is a comfortable life, case and point a system that discriminates against a group can be run competently and it would still make those people miserable.
But you could in theory have a benevolent dictator who simultaneously is tyrannical and gives his people a good life. Some dictators start out as benevolent dictators, gathering all that authority to fix some Illness in their community only to turn into normal dictators once their initial goals is done and that power starts to corrupt them (it's hard sometimes to let go of such a life).
I think the left wouldn't ever be able to keep the people happy with how they treat them even if they ran everything perfectly, discontentment would just grow in people after a while and cause major revolts.
You want to treat people fairly if you want to go tyrannical so that they can become docile, any preferential treatment should be based on what actions a person has done and not on some immutable characteristics they have so that the poor oppressed citizen can direct their efforts into rising up the ladder rather than plotting your downfall.
If a person doesn't have many luxuries because they aren't working hard they will be easier to control than if they don't have luxuries due to skin color for example. Unfairness due to immutable traits leads to growing discontentment which will then make people question why their life is so oppressed (which the dictator doesn't want)