It wouldn't have the same nice interface and searches may take several seconds, but there's only 60,000 books...
The current search box is a wrapper around Postgres phraseto_tsquery [1] whilst the Discovery tab uses plainto_tsquery, so you could play with either as an ersatz for some of these features for now, although special characters might get stripped or parsed incorrectly.
Do you know where the people you are talking about hang out online (for example, subreddits)? I'd love to get in touch with them once the features are built and for more general feedback.
[1] https://www.postgresql.org/docs/12/textsearch-controls.html
I will probably write a blog post once I've tried a few of the approaches suggested in this thread.
Most of the researchers I remember were literature scholars. While they were comfortable using computers, not many of them seemed savvy enough to write their own programs, run their own servers, or even use grep.
The corpus-search functions those researchers use include wildcards, exact-phrase specification with quotation marks, proximity searches, and Boolean search strings. When you have a chance, you might want to add a list of the syntax formats that currently work. (I tried using * as a wildcard in a phrase surrounded by quotation marks, and it didn’t seem to work.)
One small improvement you could make would be to widen the “Search terms” field so that longer search strings are visible.