The worst I've seen is where the main content is served (if you curl the website, you can see the text content is there), but it's hidden by a full-page loading animation which is removed by JS.
The saving grace in these cases is that often the reader mode would work with the HTML just fine and you don’t need to wait for the useless 3MB JS bundle which you may have blocked. The same reader mode trick sometimes works against subscribe-to-read-the-rest-of-the-article paywalls and no-scroll anti-adblock modals, too.
