Nginx
When I first started learning server technologies and how to host websites as well as other services like a personal git repository, Nextcloud, Home assistant and many others, it started with nginx. I started out learning how it all works and how to install everything from scratch on a Linux server host (Ubuntu server) This was a tedious and hard learning curve and these days I just use Nginx in a docker container with networking to proxy income requests to the right services and containers.