I have setup a full *arr stack on my home server about one year ago. I am having some trouble finding some specific content that is not listed by popular public indexers (mostly TV shows with lots of episodes). However, my friends can find the same content in stremio, so I know there are torrents of the content out there. I have asked them to share some magnet links to specific media the *arr stack has failed to source, and I have tried to trace back their origins.
What happens next is, I register to the newly found private indexers when I can, and request everything again through prowlarr. Still, there is specific episodes where are not found, and I have to get back to step 1 and do everything again. That makes me realize that my setup is not as robust as I would like.
I wonder what you would recommend me do. Right now, I can think of two solutions. I can try to register on more private trackers that are invite only by asking around (I appreciate any invitation links), or I can try the whole usenet workflow. Of course, using stremio is a possibility, but I would like to improve my own setup if I can.
What is my best bet here? There are only a few shows where I’m struggling with. For most of the content I request, my setup works smoothly.

I would like to keep it to torrents, since it doesn’t hurt to improve my setup’s resilience (after all, why not, right?). But at the same time I suspect that usenet might improve my experience, according to what I have been reading online when trying to debug this problem I’m facing.
You are right about the crack in my investigation. It seems like I have to dig deeper, and this is another indicator that maybe the usenet solution would be my best bet here, since I have already added plenty of indexers. You raise a good point about the filters configured in the *arr stack perhaps being “too aggressive” and sleeping on what would be a “good match”. I will look into that.
I do have a specific example of content my setup isn’t finding. I will give it a look later to find a specific season/episode that matches the criteria and report back. I appreciate your willingness to help!