Things that a wiki search won't find

When you search the wiki for some words like "and", "other" or "once", even if there are pages with those words they will not be found.

For a list of applicable words, see https://dev.mysql.com/doc/refman/8.0/en/fulltext-stopwords.html#fulltext-stopwords-stopwords-for-myisam-search-indexes

The reason is deep in how the database that supports mediawiki works. In other words, it's the nature of the beast.

work-around to make pages searchable

Create a Redirect page for specific, likely to be searched for pages.

work-around to find pages with stopwords

If you know a page exists, but the only content you can remember to search for are stopwords, then open the list of all pages (Special:AllPages) and search inside the list with ctrl-f on your keyboard.