I use gotenberg.dev, still HTML to PDF using chromium, but nicely packaged into a docker image. It’s then just an HTTP API call from Elixir…

Also, I think it is one of the reasons why you don't need something like unicorn / gunicorn to restart the application in case of hard error. This feature is kind of included in the VM and your application (plus more granular)

In general, you don't let your code "crash" intentionally, you mostly handle all "known cases" as you would in any other language. However, if it does crash due to an unforeseen case, only your isolated process crashes, and you can have an other process doing a restart or cleaning stuffs if needed