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?
You do not need an account at all, the apps the do are shit. RSS feeds are just publicly available text files that get updated whenever the content of the website changes. An RSS reader is basically just a very fancy text file viewer that automatically downloads all those text files and presents them in a sorted feed.
There are lots of open source and accountless RSS readers. Personally i use “RSS Guard” on Linux but there are many others. Ive used “Feeder” on android before but there are many others there too.