The Eshopbox shipping mode for a return depends on whether it is a customer-initiated return or a failed delivery return (RTO).
For a failed delivery return, the shipping mode of the return will be the same as that of order delivery.
For example, if the order was shipped via Express mode initially, then the shipping mode for the return will also be Express.
For a customer-initiated return, only Eshopbox standard shipping mode will be applicable, and its TAT will depend on the shipping zone. Learn here about Eshopbox shipping zones and TAT.