RSS feeds are a bit of a mess, but only due to each publisher's implementation being slightly different. the vast majority only send a headline and summary on the RSS feed, i then have to go and scrape and extract the article on the backend to populate the content, which is it's own challenge and i've not gotten it to work for a few sites yet.
This is also running in a semi-serverless container in Google Cloud Run (only costs me £1 a month!) so fetching and re-caching all of that when a new container is scheduled is painful, however it seems like state in the container is persisted longer than i initially thought, so it's good enough for now.