Since :! allows us to run any shell command from the vim cmdline, you run pandoc from inside vim to quickly export a markdown file with one keybinding. With pandoc and a pdf-engine installed, you can convert and open a markdown file as pdf with the following command:
1-- requires pandoc & a pdf-engine (here: wkhtmltopdf)
2-- add to the config folder: `nvim/after/filetype/markdown.lua`
3vim.keymap.set("n", "<C-e>", ":!pandoc %:p --output=%:t:r.pdf --pdf-engine=wkhtmltopdf<CR>:!open %:t:r.pdf<CR><CR>", {buffer = true})