Really love your Program - at least there is no alternatives for Android.
However, I guess you programmed it with iPad in mind.
If you use an S-Pen, finger interaction is blocked as soon as you come close with the Pen to the Screen.
Hence, holding gestures e.g. Mask-Icon + tip or slide down is really tricky within a workflow using the S-Pen.
One solution would be mapping some of these actions to the keyboard.
I already post a bug report, as Shortcuts do not work correctly - at least for the attached s7 keyboard.
Moreover: On PC (Blender) I mapped several actions on my Nintendo JoyPad (11 Buttons + 4-analog Stick directions) - quite a help for the most used short cuts. Would be great if you introduce a mapping feature within Nomad as well. Of course after the bugs are ironed out. Currently, as soon as I press one direction, I got the infinite pan bug mentioned in my bug report.
BTW: would be great to introduce it that way:
Press one button + direction (move), direction up/down (intensity), direction left/right (radius). Or even better: let the user deside. There are some remapping apps out. Simply record the joypad input and let it map to a pre-defined action.