Does it really go that slow or do you generally drive on the faster side (like 75 percentile) ?
ps : To me FSD going a little slower than max is not that big a deal. For eg. I set max at 40 mph on a 35 mph road. Usually it will go around 36 or 37, if there aren't a lot of cars zipping past us (which obviously is rare). But where it actually is useful is if the road is a new neighborhood road where somehow the speed limit is 50 mph and FSD correctly goes slower given the small unmarked road (around 25 mph). FSD also slows down at construction zones, which is good.