If you're willing to bend on the RTS thing, Tooth and Tail is an RTS game that is almost completely played with your left hand in keyboard mode - it's an RTS designed for gamepads so it only uses wasd and like 6 action buttons (rally selected, rally all, cycle selection forward, cycle back, build, sell). It uses the mouse buttons to click for the rally commands but not the pointing by default, you could rebind the mouse click rally commands to like lshift and ctrl or something like that and it should work well. But the single player campaign does get difficult towards the halfway mark