I’ve been searching for this setting and it seems that the game doesn’t have it.
I think such a feature would be a good quality of life improvement. Currently inside a rotation there might be some aimed AOE skills which you need to target at a location, same goes for bombs. There is a weird glitch that sometimes using the attack button after selecting your area your character will just attack instead of using the bomb (not sure if this also applies to skills, but it does feel incosistent to how other “non-aimed AOE” skills work AKA: auto deployment at coursor location).
I feel like if those aimed AOE skills and bombs had a setting to be used on key-up that rotations would feel more seamless, currently you can also use items and skills by double tapping the key, but doing it in a rush inside different animation locks, practically a player will more than just double tap that button, it ends in 4-6 fast presses of said button, which feels clunky.
I think using the skill on key up as a setting would still allow aiming, and reduce button mashing APM.