You should look in to Usenet + Indexers + Sonarr + Plex.

There are quite a few different guides on the subject. Basically, you would use Usenet as the backend source. Sonarr would be the application to grab all the files and automate downloading. Plex would be used for sharing. It's a whole rabbit hole.

If you're on Android, take a look at f-droid. Kind of like Google Play Store, but for FOSS.

Ive been using Unraid (not FOSS), and there are a Ton of FOSS containers that I play around with all the time. I have one for budgeting, hosting a website, updating Dynamic DNS (website), and a whole bunch of others.

Not sure if you're familiar with the terminology but WordPress is a Content Management System (CMS). I honestly don't know of many other than WordPress, I've heard of Joomla and Drupal but can't speak to anything about them other than they're CMSs, they're FOSS, and I've heard them talked about.