I would add introspection to this. Sometimes we are unproductive because we feel forced to do something that we might not actually want to do. Mantras help in some cases but I other cases you need to get to the core of why you're unproductive. For example I've swapped projects because the project I used to work on was soul crushing and no amount of mantras would've saved me there. Introspection helped me understand that I really hated that project.