Hi
@Marcos Lobo, I can recommend two books for you, concepts from these sources are battle tested in our company during consulting and delivery of couple of Internal Developer Platforms:
1. Perform Value Stream Mapping workshop with the Delivery Teams to find out pain points in the process -> thanks to it you can discover what is slowing down your teams and also get hollistic overview about their DevEx
a. book: Value Stream Mapping: How to Visualize Work and Align Leadership for Organizational Transformation
2. Think about Platform Operating Model -> goal is to properly shape interactions between Platform Team and Delivery Teams
a. book: Team Topologies
Technology is important and proper design of platform services and their APIs too, however, from my experience, technology is only part of the bigger picture 😀
Colleague from my team is also running a blog about PE, another source which you may find useful:
https://khalasa.com/2022/07/how-to-build-useful-devops-platform/