When using software like PTS, ACAD, I really hate it when I have to move my left hand/right hand to press some hotkeys.
so I came up with this:
as you can see, on default layer, I can type Q W E R T but when Fn1 is held down, I can type P O I U Y (same goes for other keys)
keycaps's gonna be a problem, but if you can touch-typing, you should be able to use the keys... ehh... promptly
with this macropad, my left hand won't need to move much and my right hand won't need to leave the mouse at all.
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this macropad is only for using such softwares, for normal usage, you need "normal" keyboard.
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you use the pen left-handed so I don't think this specific macropad would work for you but it's a suggestion.