An option to set one of your spells or items on a ring to a quick cast where if you only tap the button it automatically uses that option while holding it brings up the radial menu as normal. Probably only works with press and hold, but it would still be a nice option.
#Quick Cast from Rings
fluid bison
tribal stag
There's no notion of timed execution in the spell casting/targeting environment. So 'tapping' is not something we can distinguish from pressing and holding. You can use sticky selection and point it to the spell you want to be 'tap', but it changes when you select something else.