I totally agree with Debra but can give you some more insight into traditional book search based on other book retailers we work with
When a customer searches for a book you are either looking for:
Specific author – or authors “like this” OR
The website you have is a simple scroll and doesn’t enable someone to easily find what they are seeking – or even cluster “like books” together.
Even with second-hand book readers they are looking for a genre cluster so they can get to the heart to find the treasure. The search function doesn’t appear to work at all.
I put in “Jane” as I can see there is a Jane Harper book, but when I press search, nothing comes up. This is going to inhibit the customer flow and your website should enable ease of shopping.
You need to go back to your website structure and try and integrate some structure that means when you enter a book you can map it to genre, author and title at minimum for customers to easily locate. I would suggest this is a large part of why the site isn’t gaining tractions.
Have a look at the search on https://www.hardtofind.co.nz/ – it shows the traditionally searched functions.
Best of luck