1. The layout issue, which pushes the site.
By default the plugin is set to display the results in a hover layout mode – which you might have changed accidentally. On the Layout Options -> Results layout panel you can chage it back with the Results layout position option: https://i.imgur.com/N093wjb.png
If I understand correctly you want to display the sub (child) categories of a category, even if the search phrase does not match it, only it's parent. For that I've put together a quick code for you, which will parse the child categories for all the resulting categories, and add the to the results.
Try placing this code to the functions.php file in your currently active theme directory (copy from lin 3):Best,
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