I've wrote a few books (https://kerkour.com/books) with only markdown, https://excalidraw.com and https://figma.com
I've detailed my complete setup and shared the Dockerfile that I use to convert the markdown into ebooks (EPUB, PDF and Kindle) on my blog: https://kerkour.com/book-self-publishing-pandoc
I've wrote a few books (https://kerkour.com/books) with only markdown, https://excalidraw.com and https://figma.com
I've detailed my complete setup and shared the Dockerfile that I use to convert the markdown into ebooks (EPUB, PDF and Kindle) on my blog: https://kerkour.com/book-self-publishing-pandoc