Hello

https://support.mozilla.org/en-US/kb/firefox-ai-controls, is unrelated with your question.

Similar question https://support.mozilla.org/en-US/questions/1571937

https://www.reddit.com/r/uBlockOrigin/comments/1jrim8b/is_this_the_best_way_to_disable_duckduckgo_ai

If you wish to try uBlock Origin https://addons.mozilla.org/firefox/addon/ublock-origin

A test https://www.reddit.com/r/uBlockOrigin/comments/1jrim8b/comment/mlfvhob

The AI controls is for the AI stuff in Firefox while the AI in your screenshot is from the website itself.

You know people do not like the AI overview results in search engines sites and such when there are a lot of AI block extensions. https://addons.mozilla.org/firefox/search/?q=ai&type=extension

Hello

For information https://noai.duckduckgo.com

You can try, Add custom search engines in Firefox https://support.mozilla.org/en-US/kb/add-custom-search-engine-firefox

4. In the URL with %s in place of the search term field, copy & paste the URL of the custom search engine.

https://noai.duckduckgo.com/search?q=%s