It works for me but I double up the time, like 50minutes study and 10 minutes breaks, or 100minutes study and 20 minutes breaks. 25minutes makes me overwhelmed because so many times to take a breaks and I don't like it.
Even I double the time, I will stop for a moment if I need to get a pee or drink a water so I still focus because getting hydrated is important.
Soon other web engine will coming, first LadyBird browser and two is Servo Browser. But they're still along way to go