Updated #28 with the event from https://www.drupal.org/project/drupal/issues/3208390#comment-15200955 📌 Add an API for allowing modules to mark their forms as workspace-safe Needs work
Thanks for the response. WIth layout builder indeed there's an option, just that you are restricted to 2 levels (1 in layout builder and 1 in wysiwyg in grid). It's an edge case though that you'd need more nestings.
For those looking for an option, I've found the option to use embedded components
https://www.drupal.org/project/embedded_content →
with a custom component to use form type text_processed in which you can add the grid + these patches to allow nested modals +
https://www.drupal.org/project/embedded_content/issues/3401138
🐛
Embedding media inside an Embedded Content plugin
Active
+
https://www.drupal.org/node/2741877 →
dragos-dumi → created an issue.