Same thing happens for me on 10.0.0 with a large (34GB) cpanel backup.
On the controller try "docker logs orchd" for log details and you might want to adjust the Enhance log level at /settings/platform.
The only thing I found was looking at the importer data at /var/local/enhance/orchd/importer and doing a "docker logs orchd |& grep 5d0d6719" with a partial GUID of the importer directory from the attempt, which showed:
2023-12-17T21:59:07.795543Z ERROR ThreadId(204) orchd::api::importers::post: cPanel analyzing step failed with: internal: diesel error: value too long for type character varying(32) org_id=5d0d6719-d855-4b6d-a8f3-009bfec1189a import_migration_id=316cc367-25f7-458e-a5c9-ecf5ac4d4e56
@Adam is looking into this sometime today.
I did successfully import a 14GB cpanel backup so it might not be size causing the problem.