The idea of a 'user agent' where the 'device owner' decides 'what should be displayed and how' is ancient history, grandad.

Modern social media is delivered through 'apps' which are like web browsers, except without ad blockers or privacy settings, and with push notifications to make them more addictive, and they only show one website, and they're each 5x the size of a web browser for some reason.

This use case could also be covered with a similar technical solution. The device decides what features will be allowed to run.

If the political willpower for a better solution exists, the technical side is readily solved.