Loafy dw too much I think whichever you choose will be a wonderful experience for you in my message I talked about lots of bad stuff but that's because I'm a bit of a pessimist 😅. Yokohama it's a nice place it's outside of Tokyo so its quieter but still very city like and it's a 40 minute distance from Tokyo. Thinking of the kpop aspect Japan is pretty nice cus they still do lots of popups and concerts there, you can go to Shibuya tower records to buy K-pop merch I went there it's super cool they have a floor for every different genre of music and most kpop albums come with pobs special of that store. And Japan can be expensive but there's a lot of good thrift stores from books to clothes you can find things in perfect condition for just 100 yen. Also If u go in an exchange program it's likely there will be other exchange students you can make friends with and honestly who wouldn't want to be friends with you🤭 🌸