I mean that depends on what you argue is the definition and nature of a dictatorship. Like historically a dictator was a special privilege in the Roman Empire. So after the Roman Kingdom was replaced with the Roman Republic there was a lot of priority placed on checks and balances, so that no one person could seize power for themselves. So even the highest positions of authority were time limited and had the principle of collegiality, meaning the position was always occupied by 2 people who should keep each other in check.
Now in the case of an emergency the senat could seize it's own power and grant a former consul (highest office) some serious political privileges. Not relying on senat's consent, being the sole authority no second person, exemption from legal punishment for their actions, commander of the armed forces, able to deal out punitive measures and so on.
As this was in sharp contrast to the otherwise rather reluctant position on authoritarian rule, these privileges were limited to 6 month and the title usually also included the purpose of these privileges. So they literally had one job and close to all power available to fulfill it.
That being said the Romans already saw that fail in practice. For example Caesar already declared himself dictator for life and so de facto became a new king/emperor/tyrant. And while apparently some people over the years have advocated for such authorities that combine the entire power of the realm to solve one problem, the modern definition is pretty closely tied to that failure and the transition to an illegitimate, absolute and tyrannical power.
Also a democracy and a dictatorship are mutually exclusive either the power rests with the people (demos = the people) who rule (-cracy = rule or archy=ruler) or it rests with the dictator, who is not bound by their will.
That being said in theory it might be possible that a dictator gets it's power through a democratic mandate. That is the people agree that person X should be the commander and have all powers at their disposal to solve a concrete problem Y. In that case dictatorship is based on public consent and thus no repression is necessary.
However if the dictator only really does what people agree with anyway, there's no real argument to have a dictator in the first place. Like it's just democracy with additional dangerously authoritarian steps. The crucial part is what happens if he does something that people don't agree with. Because while potentially based in a democratic mandate, a dictator isn't bound by that mandate. So as there is no (direct) accountability and no restriction on their power through the people they could just overrule dissent.
Also the longer such a rule lasts, the more people are going to question the leader's expertise ("why didn't he solve the problem already with all that power?") and the more this excessive power and the overriding of dissent will itself be seen as a problem. Maybe even a bigger one than whatever he was supposed to solve initially.
And from that, societal conflicts will arise, that limit the power of the dictator, either by limiting his powers or disposing of him directly or simply because society gets fractured, sabotages itself and loses effectiveness in various ways.
So in order to stay in power and have power to be useful, he needs to resolve that conflict. Which is usually done by means of "carrot and stick"-politics, that is a mixture of giving the people something to appease them with their lack of political agency. "Yeah we might not have political agency but we've got these goodies..." ("bread and circuses").
Or simply repression, banning opposition and forcing people to stay in line. You can also make people believe that you've everything under control and are some god-like entity, but in that case you've also got to repress information that confirms "Nah, just a flawed human". So either way you'd rely on at least some level of censorship, propaganda and repression where the facade isn't working.
Also sure you can have constitutional monarchies where you have de jure one person as the head of state who runs the whole country, but de facto these people are just subjects for the yellow press and the actual political decision making happens in democratic institutions. However in that case you wouldn't speak of a dictatorship.
So your idea only works if they don't use and abuse their power in which case, you could legitimately ask why have them in the first place and if they make use of/abuse their power than this will create societal conflicts that they need to keep down or face a restriction of their power one way or the other.