Same, mainstream book sites are a bit broken when it comes to surfacing anything outside the one size fits all notion of "best sellers". I rarely care about best sellers. Bland thrillers, chick lit, etc. Not my thing. And the whole all recommendations converge on Harry Potter as the best thing ever is a bit lame at this point.
LLMs can be much better at recommendations. Honestly, Amazon needs to spank their recommendation teams into doing something productive with this. They clearly have the ability to run LLMs at scale. But their in house recommendation teams seem to be stuck in the pre LLM era and there hasn't been any material change in their very broken and underwhelming recommendations in well over a decade.
I actually dumped the list of books I've bought on Amazon over the last 15 years as a text file at some point and dumped that in ChatGPT. Quite interesting to see it pick up on my tastes. What works really well is taking a few books that you enjoy and asking it to find similar books. You need to set a few guard rails. Recommend new authors, don't recommend stuff I already have read, etc. But that's not a huge amount of context. Amazon seems incapable of doing this. It always funnels me to the same tired list of recommendations of shit I've declined to buy from them for years.