The feed “works”, but this is not the way to generate it: the feed needs to be generated form a collection page. Like a blog posts list, for example.
I assume you’ve based your site on the RTFM skeleton. In this case, there are no collections defined in the pages: it’s all based on pages being children of other pages.
If you want your feed to show all the pages you add to the site, create a hidden page (visible: false), define a collection on it, and generate the feed.
This is a super-helpful thread👍 Based on this info I’ve been able to add an option for RSS support with my Learn2 with Git Sync theme (a customized version of the Learn2 theme). Thanks everyone!