Overriding function or replacing interface (core)

Magento beginner here. Currently I am trying to send multiple options for a product attribute via REST api.

Since Magento isnt capable of doing this I am trying to override the add function in ProductAttributeOptionManagementInterface I understand that you cannot use preference to override an interface with another interface. So what would be the best approach?

I have tried using preference to override the class instead but unfortunately its the interface that has to be changed.