We did a test on our end to configure SharePoint as a learning content sources in for Viva Learning via follow the steps mentioned in the official article: Add SharePoint as a learning content source for Microsoft Viva Learning | Microsoft Learn. We can configure successfully for each step, and we can't reproduce the same result as yours.
Per your screenshot, you have created Learning App Content Repository and the sync process is also finished. But still can't get the content and can't see the create option.
In this scenario, we recommend you directly contact your Microsoft 365 administrator to create a support ticket from Microsoft 365 Admin Center > Support > New service request. The support team over there can involve more resource and investigate the behavior from back end as fast as possible. They also can check the behavior on your computer remotely. For reference: Get support - Microsoft 365 admin | Microsoft Docs
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.