I retired 5 years ago after the startup I worked for went public. Retired maybe isn’t the right term, as our spending has grown and we likely don’t have enough to live on for the rest of our lives (but it would be close).
In the meantime I’ve created all the projects I wanted to work on while I was working a 9-5. That’s been fulfilling and fun! And if a project isn’t I can always just stop or change it.