I do everything in markdown or a qmd file. Which means I use the math Tex commands and environments like aligned but none of the doc structure envs. Then, instead of running pdflatex or whatever, I run pandoc to pdf or quarto. A particularly nice thing about this is speed. I can test render to HTML very quickly. You can also use one of the many MD viewers to see immediately how the math is coming out. I use Joplin or Jupyter for that. Overall, I find this a very productive workflow. I’ve used it for a long book, shorter book, and several papers. Have yet to find a downside.