I have a question. This is my first time in Seoul for beauty treatments. Where's a good place to go and where should I stay?

Hi everyone! My name is Game. I've decided to go to Korea for the first time to do beauty treatments and shopping, but I'm a bit lost about where to go. I'd love some recommendations from people who have been there before. I've heard that Gangnam and Apgujeong are big hubs for beauty, with lots of shops. But I'm not sure which area is actually the best, or if each area has different advantages.

Regarding accommodation, I'm confused too. Since I want to travel back and forth a lot, where should I stay to make beauty treatments convenient? Which station is best for easy access to transportation? Any experiences from those who have been there, please share! I'd really appreciate some tips. Thank you in advance!