Is RSSTR being actively developed? It looks like it uses a single nsec for all feeds. Interesting project.
Please take a look at https://codeberg.org/nostrdev/RSSTR
The central idea is to turn feeds into "communities".
See communities (you can take a peek at https://satellite.earth ) as decentralized "websites" with a comment section included.
It replaces youtube/reddit/etc. It all depends on the client and how you want to present that content to the user, but ultimately the "backend" is the same -- Nostr.
Discussion
I don't have funds to keep development going at this moment. Maybe in the future.
Yes, one nsec does all the initial job but it gives you admin rights and you can then remove the bot's key from the admin list.
So, for example, if you now tag me (this account) on a note that says "#!mirror https://some-podcast.url/feed" my instance of rsstr will create a community for that podcast and make you admin.
You can then exclude me as admin.
Not sure if satellite.earth implemented that yet, but in theory that's how it should work.
NIP-72 is the solution to so many problems!