Two major problems:
1: very very few sites offer an rss feed anymore
2: the ones that do either only offer the headline and then just a link to the web story, or if they give a full feed, inject ads into them, where you don't have an adblocker to stop it
I spent the better part of a month trying to curate an awesome rss feed and in the end, it's still so actively hostile that it renders it's barely usable
Don't get me wrong. I want rss to come back and be as usable as it was years ago. But it's a shadow of what it used to be, and active hostile