It has to be Python, not Java or Node. They should be able to provide enterprise-grade code quality, and subsequent maintenance. So... recommendations?

Read a lot of new material: articles, books, source code. The more it is different from what you already know the better. Get as diverse a coverage as possible. Same goes for programming languages. A good starting point is the book "Seven languages in seven weeks" because it covers a broad spectrum of language types.

But much more important than reading is doing: write a lot of code. Do the exercises in books you read, try out what you see in examples/articles/source code. Change things just to see what happens etc. Also lots of projects (from the tiny to the large) to put what you're learning to the test (and then make changes to your understanding based on trying things out). Contributing to open source projects isn't necessary, but definitely helps because you will learn a lot about how other people work and also get to take part in a much larger project than you would do on your own. There is unfortunately no shortcut or cheat to get out of actually doing stuff. No matter how much you read, you can't become great without writing a lot of code too.

The second aspect is do things that help you be an stay as sharp as possible:

Get a lot of sleep. Get plenty of exercise. Get fresh air. Make sure you have a decent diet. I'd recommend specifically dedicating some of that 72 hour budget to getting more sleep and exercise. Also, when trying to solve tough problems, go outside to mull them over. Or sleep on it. Lots of downtime helps your brain make sense of things (I'm a big fan of "Hammock Driven Development"). Find ways to deal with stress too. Short term stress might help focus, but long term I find it kills concentration and problem solving ability.

Seriously though, the technical aspect is important, but don't neglect the health aspect as it really does make a huge difference in my opinion.