I'm not sure that flow and deliberate practice are mutually exclusive. The biggest example for me that comes to mind is working out. For me, deliberate practice during that activity comes in the form of focusing on getting the muscle group I'm using to contract as hard as possible. When the set starts to get really difficult and my muscles are full of blood and maximally contracted my mind is solely focused on that contraction. I deliberately practice getting a pump and when I start to achieve it, I enter a state of flow. When I go to the gym and have a good workout there is at least a portion of my workout devoted to getting a pump and forcing blood into my muscles. Empirically, my muscles have gotten larger and I've gotten stronger. Does having flow while this is happening mean I'm not doing deep work?