South Korea certainly seems like a success, with a per capita death rate about 3% of what the US saw. In fact contrary to your point, there is a very wide spread in covid impact from nation to nation. Here's a graph of all nations with 10M+ populations (scaled to eliminate Peru, which is a significant outlier that makes the graph hard to read):
And while there's lots of confounding issues here, like developing nations or autocracies with underreported or suspect data, it's pretty clear that some countries are doing a ton better than others. And it certainly looks to my eyes that among developed democracies, the nations with stronger popular adherence to mitigation strategies (in particular vaccination rates, but distancing and mask-wearing too) are the ones who are winning.
(And needless to say, the US is pretty much at the bottom of the list of industrial democracies.)
https://91-divoc.com/pages/covid-visualization/?chart=countr...
And while there's lots of confounding issues here, like developing nations or autocracies with underreported or suspect data, it's pretty clear that some countries are doing a ton better than others. And it certainly looks to my eyes that among developed democracies, the nations with stronger popular adherence to mitigation strategies (in particular vaccination rates, but distancing and mask-wearing too) are the ones who are winning.
(And needless to say, the US is pretty much at the bottom of the list of industrial democracies.)