After reading the above comment I went looking for Unicode documentation talking about the different normalisation formats. That was a point I read that surprised me because I hadn’t ever thought of it. They said search should be insensitive to normalisation form - so generally you should normalise all text before running a search.
That’s a great tip - obvious in hindsight but one I’d never considered.
The main place I've seen it get annoying is searching for some text in some other text. Unless you normalize the data you're searching through the same way as you normalize your search string.