Migrated to Feedly & Feedly has been OK but recently, soured on Feedly as they capped the number of feeds. And I've written my own RSS readers, pre-Google-Reader & now in 2021 (though it a work in progress & starting to buckle with a 300MB sqlite DB file on a shared host ;)). Those limits might not rankle many subscribers but I don't view RSS as a "I must consume every item" but as a stream to wade in, and a filtered repository to query.
The technology of a RSS reader is banal & simple in the basics. But here is where the value is for me -- the history of all the stuff that scrolls off from the most recent 10, 25, 50 posts that are available on a RSS feed. Having a large collection of subscribed feeds is like having a filtered search window into only those web sources that you assign great relevance. Even in 2021, a even more pronounced chasm to Google (or DDG or $yourFavoriteSearchEngine) searches, given all the botification / content farm hijacking / general cruft / copied content / etc. -- to search in your own set of collected RSS feeds, that go back years, even if disappear off a site's current feed XML. Or even if the site goes poof, or worse, is reappropriated by a domain harvester to siphon ad generated revenue on boiler plate content.
Google Reader, if it was championed by Google, could have served this role masterfully. (There still is, oddly, in existence Google Custom Search Engine where you can specify a collection of URLs but it doesn't to seem to work as well as searching RSS history, in my experience at least).