Damn, I need to reread that book. I'm struggling with that now; I just retired at 40 and am looking for meaning in my life with that exact issue popping up.
It was the first time I remembered someone describing the small depression one experiences after accomplishing a goal and it was funny because wasn’t something I remember hearing about from others. Mentally, I called if “post-summit malaise.”
I suppose it’s a nice problem to have but still uncomfortable. Congratulations on your retirement and hope you get to figure it out and find a new mountain to climb.