Fundamentally you can classify modern society into two groups: government and commercial citizenry.
The incentives of these two groups are misaligned and that is essentially the origin of all corruption.
The commercial citizen, his goal is to make money, compete and to do so by bending the rules and using any means possible.
The government, his goal is to be fair, to enforce and follow the rules, and to guard citizens.
When you combine these two groups the incentives collide. You get government officials who are supposed to be fair but instead they are incentivized by commercial interests so they make biased laws, take bribes and do all that shit.
To reduce corruption you really need to create societies made up of two different groups with two different sets of incentives.
Dictators are more immune to this effect because all of their commercial incentives are pretty much completely fulfilled as they own the whole country.
In a democracy the closest sort of thing I’ve seen to this is priesthood. Buddhism or becoming a monk is similar but these are not elevated leadership positions like priests.
Basically when you become a government official it should be like becoming a priest. You are removing yourself from commercial society. It changes everything. Your incentives are different and it even filters out all the bad actors.
Such a society can realistically exist. I think the unrealistic part is converting our current society into something like this.