When attempting to share a package either online or to a file, it fails with the error:
Failed to package: The table was not found.
However, this has been successfully tested with the same dataset in a file geodatabase and using a database connection with database authentication.
This is a known issue, BUG-000129031 has been referenced in cases where users are unable to publish to ArcGIS Online or a portal in ArcGIS Pro 2.5 from a database with operating system authentication. It fails with a different error but seems to be related as it fails at the staging phase.
Upgrade to ArcGIS Pro to version 2.5.2 or use database authentication. Refer to ArcGIS Pro: Database connections in ArcGIS Pro for more information.