Even a dictator still rules at the whim of the people charged with implementing their rules. Sometimes it’s impossible to get the power structure below you to change, even when you can order executions, because the incentives are broken and will keep installing people with desires contrary to your own.

The point here, then, might be to build an “insulated” city with a more direct power structure, without the involvement of consolidated power-bases like ministries or civic departments. Immigration to the new zone could be filtered to only allow in people that believe more in the lawful rule of the sovereign themselves (maybe with something like a democratically-elected governor in between) than the rule of government as a whole; and then, eventually, a military et al could be raised from that power-base to convert the rest of the country to the “new” model.