Indexers are search engines for usenet, just like trackers allow for searching for torrents. You’re curently using torrent trackers through Torrentio, which downloads the torrents through RD. RD then streams the media to you. This is convenient but as far as I know only works with public trackers, since most private trackers require you to directly upload as much as you download.
Yes, the *arr apps download the requested media through torrent or usenet. They usually run on a server (old laptop, RPi, …). They allow for searching and then automatically downloading content in the right resolution, language and size through torrents or usenet. This downloaded media might then be watched through Jellyfin or Kodi.
If you use torrents directly (public or private), always use a VPN in Germany. Downloading through usenet isn’t a big risk without VPN, just like torrents with RD isn’t risky either. Using *arr with torrents means a VPN is necessary to avoid unfriendly letters.
So, is the goal here is to replace Torrentio and hook it up to stremio by itself?
I don’t know whether Usenet works with Streamio but there might be a plugin. It might be that Streamio just doesn’t work well for german content.
Sorry, it’ll be difficult beating Streamio + RD in ease of use and cost. I’m using *arr and Jellyfin which means I have a server (desktop pc) with a big HDD running 24/7. Since I’m using usenet the cost of indexer and provider comes on top.
There just aren’t many german torrents, at least on public trackers. Might be because of this law firm that constantly sends out letters asking for hundreds of euros per infringement.
I’ve had more luck with Usenet, especially the indexers SceneNZBs and DrunkenSlug. The former is a collaboration with the forum House Of Usenet, which gives me almost always the result I want (e.g. remux, german english dual language).
Automation with *arr works great, but it’s not the type of search and play like with Torrentio + real-debrid. Downloading the entire movie/show takes time depending on the bandwidth.