I've used Typst to produce books (for https://printstack.net) and it's been excellent.

I started with this: https://news.ycombinator.com/item?id=42271078

But wouldn't recommend going via Pandoc, for example for this reason: https://github.com/jgm/pandoc/discussions/10438

Some things like #show rules can be a bit confusing. And obviously LLMs can't really help you.