My Deep Work fluctuates with my projects, but the most productive are those not on the computer, since it limits distraction.
I am a freelance videographer. So my deep work focus has been trying to learn new editing techniques. Also making graphics and backgrounds for my work.
When I deep work, i usually get something important that needs focus done. This includes working on my projects , studying for my classes or investing in self development. After the session i rather celebrate the achievement or keep working if i really got on the track.