Hi @Kingzeon, sorry for the delay on getting to this.
I don’t believe there are parameters that allow slowly decelerating the thrusters when control input changes - you may be able to make a custom flight mode to do so, but that could still be problematic if the vehicle suddenly disarms.
The underlying issue for this is regenerative braking from the ESCs, which isn’t really something that can be fully fixed or avoided from ArduSub alone.