Standardizing Date Formats in Sheets to YY/MM/DD


The Date column's format is not consistent. My default regional setting is Korea, so I think the date should be displayed in the YY/MM/DD format. However, some Date columns appear in the DD/MM/YY format, while others are in YY/MM/DD. It seems that the default is the DD/MM/YY format, and the format of some Date columns changes after the Sheet is refreshed.

Even when I apply the Date format feature from the menu, it only appears in the DD/MM/YY format. Is there a way to unify them into the YY/MM/DD format?