I spend hours toiling at work, then I finish work and switch to my hobby project, on the same desk/peripherals (KVM switch), same IDE and same tech stack, and work on it full of energy and finding it fun.
I think for me it’s the scale of my work projects and lack of deep interest in the projects themselves. Hobby projects get started because I have some kind of interest that I want to expand on by writing some code. For instance, RF and aviation are two interests and I recently wrote an ADSB message decoder with a map kind of like flightradar24 does. That’s super interesting to me, so writing that code is fun. It’s also way smaller of a project than my work projects.