You may run an import using WP All Import's WP-CLI integration. Imports run with WP-CLI tend to process about 50% faster than those run through the WordPress admin panel. To run an import, you just need to specify the import ID:
$ wp all-import run <import id>
While imports can be run with WP-CLI, you still need to create and edit them in the WordPress admin panel. After saving your import, you can see the import ID on the Manage Imports page.
In order to be run with WP-CLI, import add-ons must be written using a singleton, a class limited to a single instance. You can read more about this here: https://www.wpallimport.com/documentation/addon-dev/best-practices/