Hi Mohammed,
If you want to save all in once you should associate all the categories to one object. Then when the save button is pressed you can retrieve all the categories associated with this project over memory and then you can retrieve all the responses given in this category over memory as well. Then you can commit the lists of categories and responses and all should be saved.
Alternatively you can use on change microflows on the categories and responses, to save them as soon as they are changed.
Hope this helps!