If you're on iOS or MacOS I can highly recommend NetNewsWire (https://netnewswire.com/).
Seconded. I've been using NetNewsWire for a couple of decades, and it does the unglamorous job of displaying feeds without ads, nags, or feature churn.
Linux :/ sorry…
Seconded. I've been using NetNewsWire for a couple of decades, and it does the unglamorous job of displaying feeds without ads, nags, or feature churn.