Similar request recently for XY pads

I posted a workaround which is to put a Text over it of any size (cover the whole fader or just a part of it). Leave blank or use an emoji or text to remind you. Set long press action for text. It will continue to pass through all gestures to the fader

I'm guessing this is not a thing because you need to hold to adjust. You might want to put your finger onto a fader or knob (without moving it, just so you know you are pressing the right fader) then look back to your keyboard and play something and then slide your finger to adjust the fader. You wouldn't be able to do this if you had a hold action for a fader.