Hacker News Reader

miniflux does a pretty good job at fetching the original content, but it does not work well for sites that use a lot of JS

FreshRSS does that. You can self host it or sign up on an existing server. https://www.freshrss.org/

https://lireapp.com on iOS includes offline caching of full article.

NetNewsWire has a button to try to fetch the entire article, it works almost always. It is one of the best made Mac and iOS applications, in my opinion.

https://yakread.com

miniflux.app