>I need to conserve my mental energy for work.

Is perhaps the saddest sentence. Whats the point of working when you don't have enough energy left to do the fun stuff?

Dealing with broken Linux installs might be your definition of fun, but it's very possible to be a nerd and not find that particular thing fun, and prefering Macbooks

You might be reading into that too much. It's more likely that this person's definition of what is "fun" has changed since they were younger. Spending time with family/friends or engaging with new hobbies might be how they have fun now, and that's perfectly fine.