Most novels don't need anything more complex than a link to the next chapter at the end of the page. Maybe bold text, but a lot get by without. As such markdown will work for most. I've seen some novels with some really complex formatting, but those are rare (I read a lot of litRPG and still call them rare). However I mostly write technical documentation and I often hit limits of things markdown cannot do even though my documents are much shorter than a novel.

Pandoc is a great thing! However, lets not mix up Pandoc Markdown with standard Markdown. Pandoc Markdown intentionally adds features, that make it more suitable for academic writing, I believe.

Here are some Markdown books I've crafted:

* https://whitemagicsoftware.com/softcover/technical.pdf

* https://impacts.to/downloads/lowres/impacts.pdf

* https://whitemagicsoftware.com/softcover/jekyll-hyde.pdf

My blog describes shell scripts to use pandoc and knitr for converting Markdown to PDF:

https://dave.autonoma.ca/blog/2019/05/22/typesetting-markdow...

I wrote a FOSS GUI/CLI cross-platform desktop application to replace those shell scripts:

* https://keenwrite.com

* https://keenwrite.com/screenshots.html

* https://www.youtube.com/playlist?list=PLB-WIt1cZYLm1MMx2FBG9...

I'm using KeenWrite to write a sci-fi novel and can produce a standard manuscript format in seconds (because the content is kept separate from the presentation).

Regarding technical documentation, I extended Markdown in KeenWrite with a consistent cross-reference syntax for tables, figures, equations, etc.

* https://gitlab.com/DaveJarvis/KeenWrite/-/blob/main/docs/ref...

about keenwrite, touting "producing beautifully typeset PDF files" and not giving a single PDF example, ideally its documentation, is a missed opportunity, to say the least ;-)