One thing I've done with myself is taken up the hobby of playing prediction markets, and which I now do for a living since the pandemic (though I really want to get back to 'normal' coding job).

It involves a wide set of skills and approaches. The subject matter is basically anything that exists. It doesn't require money and you can play for free on sites like gjopen.com. I recommend the book Superforecasting by Philip Tetlock as a good introductory read.

You may find you're good or terrible at it, but most people can get better. I'm biased, but I do think more fields/levels of leadership could benefit from understanding how to get better at probabilistic thinking---or at least to have a respect for the arts of prediction and seeking out better counsel.

One thing that might be good to learn is how to find the interesting aspects of any subject, and how even within fields there can be quite a lot of breadth to the knowledge. Because to do useful work often you're going to have to focus on some area for a long period of time. If you can also develop good people skills, then being able to appreciate a bigger picture can make management another path to remaining stimulated.