Child-care isn't an option due to COVID, and since I work freelance while my wife has a full-time job, I've been the de facto Mr. Mom, squeezing in work whenever I have a free 10-30-minute block—which isn't often.
By the time he goes to bed, I'm fried from taking care of him all day, and entering into a productive 'deep work'-state is nigh impossible.
Advice to anyone considering having kids: try to live near a parent, and/or plan for childcare if you wish to get 'deep work' done. For caring for a child is, itself, 'deep work'.