Hi,
While the search results shortcode is not exactly for that purpose, in your case, you can still try using a custom URL, just append the asp_id=1&asp_s={phrase} to the query parameters:
/case-results?s={phrase}&asp_id=1&asp_s={phrase}
Use it with this setup: https://i.imgur.com/9NptW3v.png
It will trigger the search automatically after redirection.
