Medium is now my full-time income. Hence why I write so much.

Honestly, it depends on your goals, and how you want to spend your time.

I've previously spoken with a few people in a similar situation to you. They get their work done in the mornings/afternoon, and then write for 30 mins - 1 hour in the evening.

Experiment. Try writing for a lot of hours each day, and then try almost none at all. Your level of comfort will probably be somewhere in the middle.

Continue with whatever works for you. That's the easiest way to create a habit that sticks.