Speedster doesn't work(even with max speed upgrades and jokers)

I'm not sure why but almost nobody talks about this(except if it's just a me problem) but I tried and tried over and over with my shotgun to see if the speedster does anything and I really can't tell(except if I'm doing something wrong)

I tested without any jokers or any speed upgrades and I deal around 7-9 damage to the bell in the training section and 70-100 damage to the training circle things, after maxing out my speed upgrades and putting on jokers like desgrace that increase movement I still deal the same damage with no difference, is this a bug or I'm I doing something wrong?