Add some more physical hobbies. Rock climbing/bouldering, swimming/surfing, hike more often. Maybe even yoga. Right now I lift weights and jog on treadmills but I want more diversity. And I need more sun.
Start playing a competitive game again. Used to be into chess, Starcraft 2. I think this helps me decompress better than most other activities.
Read on my morning commute (25m train ride). Right now I mostly just browse the internet.
Work on a mobile game. Very bootstrappable side gig and I know little about front end.