As a DBA in the cloud era, there are many more technologies that we need to familiarize ourselves with (PowerBI, ML, Document databases) but we don't necessarily need to know the subject at the same depth or perspective that an application developer or data scientist would. In a hybrid or pure cloud environment, when someone comes to the DBA with a request, it's usually something like: "We need you to setup a PowerBI Gateway." - not "Can you create this PowerBI report for us?". I help the data analyst team setup PowerBI data sources and optimize SQL, and on a slow day I'll do something like create disk space report for use internally by our DBA team. Our pre-existing knowledge of SQL applies, since SQL is the closest thing to a universal database language - even in the NoSQL world, but I don't feel the need to learn about how to create pretty charts and graphs.
So, when looking for a book or tutorial on Azure SQL, Cosmos DB, or PowerBI - look for a book that presents the topic from the perspective of a DBA. For example, I've read the first edition of this book, and found it to be concise and useful.
Also, here on SQL Server Central, the articles and Stairways series tend to cover topics from a DBA perspective.
"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho