Hi,
Thank you for reaching out, and apologies for the inconvenience.
Unfortunately, Joomla Custom Fields are currently not supported inside Dynamic Content Articles in SP Page Builder. We understand how useful this functionality would be, especially for quickly building and managing content workflows like the one you described.
Our development team is already aware of this limitation, and support for Custom Fields in Dynamic Content Articles is planned for a future update. While we do not have an exact release date yet, the feature is expected to be added soon.
We truly appreciate your patience and understanding in the meantime.
Best regards