I think it was a mistake in the mentionned correction in Databricks

according to the documentation

Upgrade a single external table to Unity Catalog

You can copy an external table from your default Hive metastore to the Unity Catalog metastore using the Data Explorer.

Requirements

Before you begin, you must have:

• A storage credential with an IAM role that authorizes Unity Catalog to access the table’s location path.
• An external location that references the storage credential you just created and the path to the data on your cloud tenant.
• CREATE EXTERNAL TABLE permission on the external location of the table to be upgraded.

which bring to the 2nd, 4th and 5th answers.

Thank you for everyone