Last is a minimalistic static site generator for Symfony 4 applications. Once installed, Last provides a command that will simply create requests for all of your routes and dumps the result as a static file to a dist folder.
Just add it to your existing symfony application and you are good to go!
composer require fw/last-bundle
Thats it! No configuration needed, just dump your Symfony application to ./dist
Last can also handle more advanced applications with dynamic routes and more complex stuff. Please see the Github Repo repo for more information.
Find more static site generators.