The only way corruption like this can be defeated by a president who is different from other leaders who have served in the past, is if the citizens of that country can fully support and stand by their president. If other bad politicians sees that majority of the citizens are against corruption, I think it will be tough for them to go against the president.
Like in South Africa, it was easy for Nelson Mandela to fight for good governance because he was fully supported by other citizens of South Africa .
Yes, Fighting corruption is like slaying a multi-headed serpent; you need to attack at all levels of government and society to make an important difference. A strong leader with a sound plan can be a great ally, but they require the people's support to make their efforts effective.
Even with a united front, fighting corruption is a long-term effort. It takes an ongoing commitment from citizens, politicians, and law enforcement to guarantee that corrupt practices do not resurface under new names or in many different forms. And don't forget that corruption has nowhere to take refuge.