Jie is mostly used in names of people, and Jie (next to a single person) is used for outstanding people, outstanding people, etc. Later, the meaning of the word Jie (next to a single person) was merged into Jie, and Jie (next to a single person) was cancelled. The character Jie has also existed for a long time, but the reform of Chinese characters merged the two characters into one character. In fact, they are two characters, just like mian followed by mian (next to the character wheat). Therefore, simplified characters do not come out of nowhere.
The word "Jie" became bad because of Xia Jie's existence, so this Jie is not used in the name.
This is not comprehensive. You can check "Shuowen Jiezi" and "Kangxi Dictionary"