I dabble at home, but it looks nothing like work code. I also started writing code for fun as a kid, before doing it professionally. I do find it hard to do much after a day of work and taking care of family. (I've just been laid off after 20 years at my company, so I guess I've got more free time now.)
Last year I wrote a self-hosted dependent typed programming language, after spending a couple of years helping out with Idris and learning how those languages work. I started that process because I was pretty burned out and needed something stimulating to do.
Before that, it was little things, like code to read various binary file formats. E.g. a read-only sqlite implementation, code to read realm databases, reading indexed db off of disk for various browsers, decoding apple notes database, decoding iOS backups.
Like you I put an enormous amount of personal free time into software engineering in my career. It had massive benefits that have paid out in many, many ways.
Some days, when I wrap up work, I feel burnt out and just watch TV shows or make food. Other days, I get so into what I'm coding (for fun/edification) that I look up and it's 10PM. It helps to have a long term view- my expectation is that I will be working on projects for a decade or more, slowly getting more knowledgeable, so i don't see a need to rush or overwork.
Last year I wrote a self-hosted dependent typed programming language, after spending a couple of years helping out with Idris and learning how those languages work. I started that process because I was pretty burned out and needed something stimulating to do.
Before that, it was little things, like code to read various binary file formats. E.g. a read-only sqlite implementation, code to read realm databases, reading indexed db off of disk for various browsers, decoding apple notes database, decoding iOS backups.