It sounds simple on the surface. You copy a link on a site into a feed reader app. Then whenever that site updates you get a nice readable article on the app.
But that sounds like something that could be accomplished locally. Why does every RSS reader I run into require an account or otherwise rely on the cloud?
It can absolutely be local.
For podcasts I use AntennaPod, for news I use Feeder. Whatever your use case, there is probably a local, well-made FOSS option.
Nonlocal uses have additional capabilities, such as syncing across multiple devices. I also use gpodder.net for podcast syncing, although there are self-hosted options for this as well.