For those people who are unfamiliar with DJI GS Pro, you might want to include a screen capture of the type of mission you are asking about.
If what you want is a mission in the shape of a grid for mapping purposes, Litchi does not provide that capability. However, there are a number of 3rd party applications that do provide that functionality.
The Virtual Litchi Mission application does provide a “Grid Mission” option. However, it is only a very basic mission without much flexibility.
A number of people use ancient.land. More details can be read in this thread: