Some fantastic hobbies involve learning a new skill that'll serve you in the long run outside of tech, or teach you something interesting that will last after you drop the hobby. I personally love making things, especially food-related things and so I've been a hobbyist baker for about a decade. The Bread Code on GitHub was a fantastic introduction and taught me the basics to branch out and discover better baking techniques. That's the main one I've stuck with.

I've also dabbled in home wine making, cheese making, preserving and pickling, and they've all given me a deeper understanding of fermentation even if I've not stuck with them as much as I did with bread. However, if I go for a wine-tasting or a beer brewery I now know what they're talking about when they go into the process of it, which is a good conversation starter if nothing else.

There's also gardening, but that's mostly something my partner stuck with instead.