I want to change my global account to a Korean Kakao account

Hello
I am Korean.
But I went on a lot of overseas business trips
I had to play a game
So I had to create a global account
But now I don't go abroad
So I want to change my global account to a Korean (Kakao) account
Read this and tell me how
It's too hard to use the exchange
It's hard to pay even if I try to buy a paid item