Get yourself a nice newsgroup, and an nzb indexer(search site for newsgroups) . Install nzbget, sonarr and radarr and Google for the parts you get stuck on.

I recommend a 2nd newsgroup subscription at a different place, because (in layman’s terms) to appease the dmca strikes they delete a single file of the download, and chances are a different server deleted a different file, so your downloads are complete enough to parse the rest together.

This is the one I used years ago: https://blog.harveydelaney.com/configuring-your-usenet-provider-and-indexer-with-sonarr-radarr/

The nuts and bolts should be the same. I imagine his recommendations on what backbones and newsgroups to subscribe to are out of date, though.