I’m a fan of KDEs Akregator. It does a great job as a feed reader and shows the contwnt of an entry in a simplified reader mode. However some feeds jist dont display the full arricle in their feed entries so you’d have to follow a link there. But even thats sth that makes Akregator awesome: you can specify the command thats used to follow a link and most browsers have the option to open a page in reader mode via the commandline. So from what I gathered thia should pretty much do all you want it to and then some.