What are the best hands on the approach to learning MySQL to be a database administrator?

That’s a start. There are plenty of resources to help you get started there. Getting certified as a MySQL DBA would help a lot and give you a structured way to learn the craft

Becoming a MySQL database administrator requires skills in the following areas at a minimum:

• Installation

• Backups

• Configuration and performance tuning of the server

• Restorations of backups

• Setting up replication

• Setting up multi-master replication

• Reading, writing, and performance tuning queries

• Understanding stored procedures, functions, triggers and events

• Learning how to create and maintain tables and views

• Understanding when MySQL is a good/ appropriate solution to a problem versus other persistence layers

That’s a start. There are plenty of resources to help you get started there. Getting certified as a MySQL DBA would help a lot and give you a structured way to learn the craft. The real question is what do you want to do with the knowledge?