I don't think I understand correctly. From the screenshot I see you have grouping enabled by custom post type. The category results appear on the bottom of the list in the 'Other results' group, like they are supposed to. Is this not correct?
I might need more information to be able to help you:
– Do you not want post types as results, only categories?
– Do you not want to group the results?
– Do you want to display the categories first then the results?
– ..or is the problem something else?
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