I’m not a cynical person. I say that if you can’t distinguish between Gyeongbokgung Palace and Changgyeonggung, or between Haedong Yonggungsa Temple and Haeinsa, then you’re not looking closely enough. You might as well say that Westminster Abbey is the same as the Notre Dame.
The architecture is very similar over at Changgyeonggung Palace, which was also built during the 14th century and was temporarily levelled by the Japanese a couple centuries later. Same shapes and colours, though there are more hallways connecting the various buildings. This was probably appreciated by the monks during the long winter months - again, heated floors.