Accessible open textbooks in math-heavy disciplines

For the articles on my website, I have a pretty janky workflow where I write a LaTeX document that I compile both to a PDF and (using Pandoc) to HTML, which I render with KaTeX. I've been in the market for a while for something that's less fragile but which can still produce both a PDF and visually appealing HTML output starting from a LaTeX source, and it seems like some of the ideas listed here might be what I want! Thanks for the link. (That said, if anyone has a particular recommendation, I'd love to hear it!)

I’m lazy. I just extract the abstract from the tex source and put a link to the PDF. That is however quite different and not public in my case.

Turns out from a technical documentation consumer perspective it’s easier to save a PDF than feck around with web pages and try and save them.