It’s worth mentioning the work that BeaconCMS has been doing in this space, not only creating a widget/component-based CMS with WYSIWYG drag-and-drop UI but also with mixing markdown, HTML, and HEEX in these dynamic widgets (hence doing runtime compilation).
And there’s our work on Bonfire (a federated app framework rather than a CMS) which is fully modular (every piece of code lives in an extension/plugin meaning it has its own repo and can be included as a mix dependency) and allows admins and even users to toggle extensions (using something like feature flags that checks if extensions or even individual modules are enabled or not). But we’ve chosen to not try for installing new extensions at runtime, instead you can define which extensions should be available in config (including some you don’t want enabled by default) and then let CI build a release that includes all necessary code.
