As I complained in a query form in the Koha chat,

Z39.50/SRU search question: Is there a way to search verbatim for a string that I'm missing? Ex. If I try putting quotes around a title I'm searching for, it finds nothing because no titles contain those quotes, but otherwise it seems to just find anything with any of the words in the title, which for some titles is uhhh quite untenable 😅

In my other Koha chat (me bugging Mandy incessantly),

id blame more koha on that... other sru/zs searches are not built the same
like, sirsi dynix had a decent one
you could match on several levels
koha is pretty rudimentary

And I said,

I mean, this is below rudimentary
This is "I have done better in 5min for a work thing" level of searching lol/arghh
The likelihood I personally improve Koha's Z/SRU search just out of personal frustration is not high, but it is very nonzero!
Unfortunately Koha is mostly written in Perl, which I have mostly avoided learning over the years and has especially been a nonissue for the last decade