The “Beat your PB” sessions are part of the Freeletics experience-and as the workouts are standardised it’s very easy to track progress.
However, a little workaround for you-you can almost always get an “Interval” instead of a “Beat your PB” session if you use the adapt session and select the “I need to train quietly” option. Sometimes you might also need to use it along with the “I want a different session” option.
It won’t always give you an interval, but in most cases it will.