I would disagree. Bergoglio is the worst pope.
Even the Borgias, as depraved as they were, never tried to change the doctrines of the Church. They were hypocrites and bad people, but at least they did not try to deceive the congregations with false teachings. They lived decadent lifestyles but it did not go past Rome.
Bergoglio is more dangerous because he is leading people astray with false teachings. It would be better if he lived like a Borgia and left the Catholic teachings alone. (I am not saying that the popes should live decadent lifestyles)
In which case you have rivals for “worst popes ever” in the persons of John XXIII and Paul VI - the Popes that inflicted Vatican II on the RC Church and paved the way for Francis.