@moss
For duckduckgo, this should work:

https://noai.duckduckgo.com/?q=%s&noai&df=1980-01-01..2022-01-01

This is intended to be used as a custom search engine on firefox.

https://support.mozilla.org/en-US/kb/add-custom-search-engine-firefox#w_add-a-custom-search-engine-in-settings