Ya that landscape can be rather overwhelming.
I recently read through Cloud Native Infrastructure and found it very useful for understanding the underlying work. As for Kubernetes itself,Kubernetes: Up and Running was a great read, same with Nigel Poulton’s Kubernetes book. That being said I haven’t come across a book that addresses the landscape itself.
I found a good place to start is breaking things down into more digestible chunks and defining what problem your looking to tackle/learn about is. The CNCF TrailMap attempts to address that. While it is focused on just CNCF projects you can apply those categories to things in the CNCF Landscape.
I recently introduced Kubernetes to my organization and grabbled with this exact same situation and did a talk at this years kubecon about it (sadly not on youtube yet).
I’d love to help more, if you have any questions.