If you are having suggested item returning no results, you may check if there are any applied filters in your Query Suggestion and review if you have any records that match those filters.
You can write a script that checks and creates a new filtered query suggestions index based on your first one, ensuring that it will have matches.
To do this you can browse your query suggestions index. Then, for each suggestion you find you can run a search using the suggestion and the filters you are using on your site. If the search finds a result then you can add this suggestion to a new "filtered query suggestions" index and if not you can skip it.
Of course this would require a significant amount of coding and also would use search operations.
Second option is to remove a specific keywords would be to make a front end change to your autocomplete to hide the keywords you don't want to show.
There are more details on how you can modify the autocomplete here: https://www.algolia.com/doc/api-reference/widgets/autocomplete/js/