Historically, the emperor's daughter was called a princess, and the title "Gege" became the title for other members of the royal family and the daughters of nobles besides the emperor's daughter. This problem only appeared in the Qing Dynasty. Before that, the title princess had never been used. After Huang Taiji came to the throne, according to the Han system, the Khan was changed to the emperor, and Princess was changed to Princess. Princess has always been a Han title, and Princess is a Manchu title. Exclusive, but because the Mongols also contributed to the Manchu world, the daughters of some Mongolian princes can also be called Gege.
In our traditional concept, a princess is the daughter of the emperor. This is the name of our Han people. Princesses in the Qing Dynasty are also divided into classes. During the Huangtaiji period, the queen's princess was called "Gu Lun". The daughters of other concubines are called "Heshuo". "Heshuo" means place and has a lower status than "Gu Lun". The name "Ge Ge" is usually used in informal situations. You can call the princess "Ge Ge".
In the TV series "Kangxi Dynasty", Kangxi's favorite Lan Qi'er is right. Normally the palace people would call her Lan Qi'er, but on some big occasions, for example, Lan Qi'er would be given a marriage. Princess Lan Qi will be written on the edict, which is a more formal occasion. During the Shunzhi period, the princesses were assigned grades again, and the daughters of the more distinguished princes were named "Heshuo Gege", and the lower-ranked "Duoluo Gege", "Gushan Gege", "Gege" means "Miss" in Manchu. Meaning, Ge Ge can sometimes call other women Ge Ge, or concubines whose status in the prince's palace is lower than that of his direct descendant Fujin and side Fujin.
So to sum up, there are three differences between "Princess" and "Gege". First, they have different origins. Princess has been used to describe the emperor's daughter since ancient times. Gege has a wide range of uses, but most of them have to do with the royal family. The second is the difference in status. The hierarchical titles of "Princess" and "Gege" can also tell the status of a woman. The third is the different origins. Princess is a Han title, which first appeared in the Western Zhou Dynasty and the Warring States Period, and Gege is Manchu title, exclusive to Manchu and Mongolian people.