You’re right, that the supernatural parts did not happen like a katabasis story.
But you are 100% wrong that 100% didn’t happen.
There are serious issues with the work, chief among them being Homer combining the 14th century Mycenaean conquest of Anatolia with the 12th century sea peoples retaking of Wilusa from the Hittites. But many, many of the fragmentary details being combined into a mythological history did in fact occur, including Odysseus’s one day battle with Egypt (Merneptah’s Libyan/sea peoples war).