I'm like GP too, I'm usually at my peak performance somewhere after dinner. Used to be a stereotypical night owl, but eventually life forced me to act like a morning person (small kids + partner who is a genuine, bona fide, textbook morning person slash productivity beast).
Close to a decade of that lifestyle, and my body didn't adjust. In my case, there's no insomnia - I indeed start feeling tired around 21:00 - 23:00. Just that my performance curve didn't shift accordingly; only thing that's changed is that I had to give up my most productive parts of day (afternoon, late night), because I'm too tired to do anything at that point.
Close to a decade of that lifestyle, and my body didn't adjust. In my case, there's no insomnia - I indeed start feeling tired around 21:00 - 23:00. Just that my performance curve didn't shift accordingly; only thing that's changed is that I had to give up my most productive parts of day (afternoon, late night), because I'm too tired to do anything at that point.
I'm open to suggestions on how to fix that.