I wouldn’t mind if it was my 4 best hours a day, but it’s the 4 hours after work and dinner when my energy levels allow for a half effort workout and a bit of reading or TV.
One of the best things I did for myself was moving all of that free time to the morning. Now I wake up at 5, have coffee, exercise, play or work on whatever hobby has my attention at the moment, then work all day. I have loads of focus and attention and energy for my fun things.
Evening is pretty much make dinner, eat, relax for a bit and be in bed reading by 8.
This can be a good strategy until you have young kids. After then, they often hear you get up and then seek you out to get help making breakfast or want to sit on your lap.
But otherwise, it prioritises your side project while you're fresh in the morning and puts relaxing (movie/TV/etc) for when you're fading at the end of the day.
I recently found myself in the same position by being in Asia while working for a European company. All my free time is in the morning without having to wake up early (in the dark). I go surfing or swimming/gym and then work 12pm-11pm with some breaks for lunch and dinner. I go to bed straight after working, which means I've stopped drinking. It's made a huge difference to my quality of life and I hope I can keep this up forever. Having to wake up and go straight to work seems like a depressing thought now.
Evening is pretty much make dinner, eat, relax for a bit and be in bed reading by 8.