Well, the future is for the cloud in general. And yes I believe that Azure is going to be the number (1) recommended cloud provider.
As for me I am an Azure certified Solutions Architect, also certified in AWS and GCP. And in the past 5 years a lot of customer would come to me and ask which cloud provider to go with?
Typically the answer would be "It depends!" but last couple of years I always suggest Azure. I have done a number of migration projects on AWS and GCP. Now with 100% confidence, I can tell my customers there's nothing that other providers can offer more than what Microsoft offers. And what I really like about Microsoft is they do listen to their customers, and they have lots to offer more than what other providers do.
As for the the value of learning Azure! I believe that no matter what you role is! I see that the market gives a huge + for anyone with cloud experience in general.
And once again :) no matter what you role is, I believe that having the Azure Fundamental course (AZ-900) is a huge ++ this should be the start of your journey to Azure.
Here's everything you need to know about the AZ-900 https://learn.microsoft.com/en-us/certifications/exams/az-900
As for the income! I think it depends on the path you choose? Years of experience? and unfortunately the geographical location!!
Try to go to Microsoft learn and browse courses, available trainings, and certifications there. Microsoft documentation and training is one of my best GoTo website! To learn anything Microsoft related.
They have done such an amazing job with their documentation & keeping them up to date.
https://learn.microsoft.com/en-us/
Best of luck with your journey