I'm not sure the governmental form of republic is terribly useful to discussions of fairness or freedom in societies. Norway, Sweden, Denmark and New Zealand appear at the top of the Democracy Index, and are democratic constitutional monarchies. North Korea, Syria, Democratic Republic of Congo, and the Central African Republic are republics and among the most tyrannous societies.
> North Korea, Syria, Democratic Republic of Congo, and the Central African Republic are republics and among the most tyrannous societies.
I don't know about every single country on the list, but at least the one I am somewhat informed about (North Korea) is a republic only in name, as it is pretty much an authoritarian dictatorship state controlled by the military class.