How can rulership be both wise (just) yet avoid corruption (for short term benefit, and/or the benefit only of the ruler or ruling group).
It is an old problem, going back to Plato and Aristotle and their reflections of the possible types of rulership.
Nobody has improved on Aristotle's division into rule by the one (monarchy, dictatorship), the few (aristocracy, oligarchy) or the many (democracy).
But Aristotle can do no more than describe the advantages and disadvantages of each 'system' and state a preference.
Monarchy is potentially the best and highest form of government, but also potentially the worst; democracy vice versa, and oligarchy somewhat in the middle.
In secular terms, in worldly terms, there is no other answer.
Modernity thinks it has another answer, which is to make rulership impersonal - in other words to rule by an abstract system.
In practice this means rulership by a system of rationally-interlocking laws and regulations; created and implemented by bureaucracies that depend on committee voting.
Yet rational bureacracy is not a solution to the dilemma, because it is not rulership at all.
'Rational bureacracy' is impersonal rulership only because it is inhuman rulership.
Rational bureaucracy is not impartial with respect to humans, it is indifferent to humans.
Rational bureaucracy is also, as we now observe, utterly corrupt (short-termist, fractured and fragmented by covert self-interest and unresolvable in-fighting between the rulers).
So we now have not an Aristotelian compromise between the potential and the actual, but the worst of both worlds: corruption without limit (short-termism to an extent unimagined in the past), and a rulership under which nobody ultimately benefits: not even the rulers themselves (not even the bureaucrats).
Since there is no answer to 'who guards the guardians' in worldly terms, the only potential answer is in otherworldly or transcendental terms.
Rulership can (at least for a while) be both wise (just and long-termist, for all the polity) and relatively uncorrupt (i.e. neither short-termist nor pursued for the exclusive benefit of the rulers) in a situation when rulers and ruled are devout: united in worship and guided by transcendental revelation.
(An example, King Alfred the Great of England.)
But the necessity for devoutness rules out (in practice) large scale democracy.
For large societies there is only (theoretically) a choice between divine oligarchy and divine monarchy - and the conditions for a wise and uncorrupt divine oligarchy are extraordinarily unlikely.
The only example of divine oligarchy (wise and uncorrupt leadership by small groups) that I can think of are situations such as prevailed in the early Christian Ecumenical councils and the translation of the Authorized Version of the Bible under King James I of England.
A small devout group united in prayer and with a sincere common aim.
At any rate, there is no secular solution to the problem of 'who guards the guardians' and it is a waste of time and misplaced effort to refuse to accept the fact.