Have a kid. If you need more to do, have a second kid. Only halfway kidding. You know how therapeutic and enjoyable it can be to spend an hour drawing or building Lego or even Play-Doh with a kid?
Its kind of like a hobby, but it costs more, and you won’t/can’t get sick of it and change your mind.
I also like polishing individual bicycle cassette cogs to a shine, and repacking hub bearings.