I already use LibreWolf, so i’m not too worry by the FireFox integration, but i was bored to manually disable the DuckDuckGo AI results each time. This helped quite a bit. You can also check the GitHub page below where the developer explain how it works.
https://addons.mozilla.org/en-US/firefox/addon/disable-ai/
https://github.com/jruns/disable-ai
In alternative you can also make noai.duckduckgo.com as your default search engine.
Sarcasm escapes you.
Wait, what! Where did that bastard go!