Japan colonized areas of northeast Asia and Southeast Asia pretty brutally over the course of 50 years or so. In addition they forced some of the population to learn Japanese. It wasn’t a kid gloves colonization.

For that matter the US was a colony of the British Empire and yet came to do well. Russia had suitors attempt colonization a few times but as history tells us that failed, they have vast resources, they have had some great minds yet have come up short. I think imperialism is a distraction. From your POV Korea should be dump. It was colonized by Japan and later had US approved military dictators -a big no no in your books. But see where they are today.