IMHO, it's much better to use markdown generally and insert latex only when it is completely necessary.
A latex usage example is creating a tikz picture or for introducing \pagebreak or \framebreak in pdfs or beamer presentations.
For the rest of the cases, markdown is much less verbose and can accomplish the same.
I find that this route is best for documents that you are writing: you can focus on the content and use a nice markdown editor like Ulysses without having to worry too much about formatting.
On the other hand, when I'm trying to typeset a pre-existing text for reading/distribution, I find it a lot easier to copy and paste the text into a latex template and then tweak it incrementally until everything looks the way I want it to.
I've also started generated latex PDFs via the Jupiter notebook. They have a quick and easy preview, plus markdown + latex math + code integration that's easy.
Is there some good ready-made templates around one could try without too much hassle?