@ybaptiste The recommended workflow does clone the product line items or notes or any other object, just copy deal to deal properties which is a huge problem.
(You can use workflows to create a new deal and copy data from the existing deal. )
There is a third-party app" clone attack" that clones it pretty well but why do I have to pay additional fees per month for a basic feature that Salesforce and even Zoho CRM have.