Ask HN: Desperately bored mobile dev wants to get into machine learning

I've worked in mobile my entire career. In the past ten years I've helped build some of the most successful mobile games for EA, prototyped crypto apps for payments similar to Apple Pay and worked for Australia's largest mobile consultancy. Most Australians have an app I've worked on. I moved to the US a year ago to work for a large tech company in Seattle.

Right now I'm desperately bored. I'm maintaining an app at work that has been poorly written and I don't have the approval to refactor much of it. The culture of this team has no passion for the work they're doing. I'm stuck at this company for the next year and I need a challenge. I've decided to study machine learning.

Right now I'm reading Machine Learning by Jason Bell. It seems like it's a good introduction. Other than reading and working through the examples in the book I'm not entirely sure how to get proficient at machine learning where I could consider working in it professionally.

I'm curious to hear other people's experiences studying machine learning outside of university. Was it worth it? How and what did you study? What side projects did you have?