Advanced search for readers

We have an upcoming project that could feature as many as 100 short “chapters” combined into a single book. Chapters would be written by different authors, with many authoring several individual chapters. Chapters may cover a number of different themes.

Right now, the search bar available to readers provides rather generic results based on the entire book, or keywords linked to the book project as a whole.

Is there a search plugin available on Pressbooks that allows us to assign searchable keywords to specific chapters? Or allows the reader to filter the chapters by author, or theme (I’m assuming we would have to tag the theme terms in the code somewhere)?

Or is there any other tool available that provides the reader with a more robust search option within a specific book?

We’re not really programmers here, but can get into some light coding if there is an available tool that isn’t too technical for us.

Thanks.