Morning vs. night writing personalities
The advice to write first thing in the morning is everywhere. It works for many writers because willpower and creative energy are often highest before the day has made demands on them. But night writers exist, and they are not doing it wrong. Many produce their best work after 10pm when the house is quiet and the internal critic is subdued by tiredness. The question is not which is better but which is better for you. Track your output at different times for two weeks. The data will show you your window. Build your routine around what works, not what sounds virtuous.