Thank you for the detailed explanation.
I need to be honest — the workflow you described still doesn’t give us enough clarity on where the configuration issue is occurring, so at this stage we are not able to reliably reproduce the behavior from the steps alone.
To better understand your setup, could you please clarify one key point:
Are you using Joomla Articles with SP Page Builder Dynamic Content (Article layout), or are you creating a completely new Collection inside Dynamic Content and then trying to bind it to the layout?
The reason I’m asking is that, if a new Collection is being created in Dynamic Content without any properly linked or populated data source, it can appear exactly as you described (empty collection, no linked categories, and no available mapping in the detail view). However, if you are working with standard Joomla Articles + SP Page Builder Dynamic Content, the configuration flow is different and the issue would need to be checked in another area.
From your description, it also seems possible that the collection is being created before any data source is available, which would explain why nothing appears in the layout or detail view.
To avoid confusion and speed up the setup, I strongly recommend going through the official Dynamic Content getting started tutorial, as it clearly explains how collections, data sources, and layouts should be connected:
https://www.youtube.com/@joomshaper/search?query=dynamic%20content