In Firefox and its derivatives, you can add the non-AI version of DuckDuckGo as a search engine by going into Settings > Search > Search Shortcuts > Add and then giving it a name of your choice with https://noai.duckduckgo.com/?q=%25s being put in the “URL with %s in place of search term” part. You have to remove the 25 part from the URL though, that seems to be a Lemmy quirk with posting a link.
I don’t know when they made this available, but I’m learning about this now and it’s super useful if you hate LLMs and also use a browser that clears cookies on close (such as Mullvad or LibreWolf).
I think Chromium based browsers had something where you’d need to open the homepage of the search engine (https://noai.duckduckgo.com/ in this case), right click on the URL in the address bar, and then click “Add search engine name”. Not sure if that still works though.