Sorry just getting used to notifications in lemmy so I didn't see this till now. But @hydra@beehaw.org summed it up perfectly.

You need A client, an indexer, and a Usenet provider.

I use SABnzbd for my client, I've got several different index sites, and 3 providers. One of which is a yearly unlimited subscription and the other 2 are bucket plans where I buy access to a set amount of GB to download and once I use it, I either buy more or lose access. They basically serve as backup servers if something can't be found on my main unlimited server. I use prowlarr in conjunction with radarr and sonarr to manage my indexers and shows and movies, and use SABnzbd as my download client, connected to my Usenet provider. It works beautifully once you get it set up right.