Is soundproofing in Korean apartments really possible?

How can I soundproof an apartment in Korea? Lately, it seems like the walls are so thin that noise comes through easily. This is especially severe in busy areas like Gangnam or Hongdae, and I'm curious if there are good methods for soundproofing. I've heard that noise issues often arise in apartments due to thin walls. This problem can be quite concerning for foreigners living in studio apartments or officetels where soundproofing is poor. I've heard various methods for soundproofing, but I'm not sure which one is the most effective. If anyone has successfully soundproofed their place in Gangnam or Hongdae, could you share what methods you used? I'm particularly interested in opinions on DIY soundproofing materials or professional installation services. I would appreciate your advice!