I've had great success with the Pomodoro technique. It really increased my focus and decreased stress. I plan my day out in time blocks, then I focus one item at a time.

The timer isn't a deadline. It just notifies you of when the 20 minutes is up. I don't even look at the timer when I'm working.

I believe there exists an optimum methodology to optimize whatever the desired output KPIs are for a person at any given time and that what doesn't work for one is literally optimal for another person. Some people have achieved success with a methodology, some will fail miserably. Some people will do far better with a suboptimal method than many that find their optimum method as well. The question is about finding the solution as fast as possible for an individual and with the best accuracy.

Personally, I think I need some sense of urgency to perform deliberate, spaced practice reliably due to a strong history of what may be something like ego depletion (not really well supported). Pomodoro has worked better for me than most methods as long as I have sufficiently well crafted goals because it forces breaks as well as time boxing for results when I have a tendency to overengineer (along the same lines as SMART requirements). Like exercise, if you feel really comfortable, there's a strong possibility that you are not making the desired progress. In such cases, those that are motivated positively by the stressors are predisposed to improve over those that do not get motivated in such a manner even if that would be the most optimal technique globally.

YMMV, having the timer ticking away helps to keep me on task: by picking up my cute little ladybug-shaped timer and twisting it, I have made a promise to myself that I will work on This Thing for the next 25 minutes.

If it stresses you out instead, then yeah, find another method. But I found it to be really effective.

Learning Hot to Learn course on Coursera (highly recommended) talks about procrastination a bit and they do recommend a Pomodoro technique to fight it.