Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear Val N,
Thank you for posting in Microsoft Community.
Based on the description, you cannot remove the contents in Viva Learning. Apologies for the inconvenience caused to you by this behavior.
Per checking on the official article Add SharePoint as a learning content source for Microsoft Viva Learning | Microsoft Docs, we can delete content by following the steps below.
After more than 24 hours and your contents still showing on your Viva Learning, I would suggest you to please raise a support ticket Get support - Microsoft 365 admin | Microsoft Docs. Our support engineer will help you to check it from backend to remove your contents on your Viva Learning.
Your kind understanding is highly appreciated. Stay safe and healthy always.
Sincerely,
Zee | Microsoft Community Moderator