Congrats on your transition to DevOps! It is an excellent decision.
Kubernetes is a cornerstone in DevOps and Cloud world, and you definitely should learn it. I can't give you an exact learning path for DevOps, but Kubernetes should be something that you should learn immediately after public cloud foundations and general CICD knowledge.
As for our book, It is one of few books that were written based on real-life experiences from real projects on productions, and it has very essential knowledge for any DevOps and cloud engineer who will be dealing with production on K8s. However, it is not an introductory book to K8s, and to gain the full benefit from the book (which by the way covers other areas for DevOps like IaC with Terraform) is to go through beginners guide at https://kubernetes.io/
then start reading the book.
Best of Luck!