Yes i lived in sk for 3 years. Havent made it there unfortunately.
My wife has been to Jejudo a couple of times—she loves K-dramas and Korea in general. She goes with her fellow K-drama friends. My only time in Korea was on a one day layover waiting for a flight to Japan, so didn’t really see anything. And it was in the old days before democracy when the military still ran things, so back then it had kind of an oppressive feel with a lot of heavily armed policemen around. It’s totally different today.