The major factors that you can control are speed, your effort, motor assist and for me with a cargo bike the amount of weight I haul. Riding an e bike is about adjusting these factors while always keeping in mind the limits of your battery. It takes a lot of self control to keep the assist low if you really want a workout. I would guess you will end up keeping the boost higher to cut your commute time while hopefully still pedaling hard and getting a workout.