What is your product launch process and how did you get internal buy-in for it?
In all product marketing teams I have worked for we came up with product launch treatments for the types of product launch. The types of launch can be "New SKUs", "New Features", "Minor Features" and so on. It's best to have a product launch playbook template designed for each type with consensus from all functions that can include product management, marketing, enablement and customer success. Make sure that product marketing project manages each launch and is ultimately responsible for the success of it.
In my opinion this is the best and most efficient way to get buy-in from all teams if product marketing champions the process and is on the hook for making it successful.