The cognates are what make it so easy. It's like adding -o to English words to get Spanish; you can just add -u to Korean to get Japanese pronunciation like 약속 --> やくそく
Cultural concepts translate directly, e.g., 선배/후배 --> 先輩/後輩, honorifics in general, 月火水
Also you might enjoy this: https://youtu.be/HiUGWXe6Yzk?si=8g35dQxxbXOGW27c
trying to blame the victim