Be sure to read the detailed documentation at the Ditto website to learn exactly how your copy will be handled with respect to what is copied and what happens in specific cases, say regarding members or custom fields in one workspace but not another.
Asana offers Duplicate Project and export/import, but these only work one project at a time and are not nearly as flexible or complete as Ditto. Asana Support regularly recommends the use of Ditto.
Many of us are so appreciative of this great app that we have upgraded to Pro to support Ditto’s development (it’s a total bargain, low one-time fee).
PS No financial interest; just a happy, long-term customer.