For me, I find the Pomodoro technique really effective, but there's a key caveat, which is that you try to focus on one thing at a time (which flies in the face of using multiple AI agents working on x number of things at the same time).
Another angle to explore is how much of the process of software development that we do manually can we automate, particularly the parts that still require human input (like code reviews). That may also help with reducing the cognitive load.