For the last 10 years I've been working mostly on CI and CD automation for a few projects that as part of their offering tried to automate the deployment for their clients.

In general when you try to simplify a process you increase the level of abstraction which leads to additional complexity in terms of customization and integration with third party systems and tools. Then you decide that it is a good idea to offer integration with the third party systems and tools and you increase the abstraction even more which increases the complexity even more. Also in the end you wonder if you are in the CD tools business or you are offering your core product.

It is much more productive to develop the product in mind with the tools for deployment that are already available. Unless you want to have a product and a "Services" division that configures and operates your product for the clients...