Hard to say without knowing anything else about you. The Canyon Commuter Sport 8.0 is perhaps one of the most aggressive of the bikes marketed as commuter. It's going to be a sporty handling bike and if you don't ride it like a sporty handling bike you won't be comfortable on it. Is it too late to send it back?

Otherwise, did you get the frame size that they recommended for you? Or is it too big and you are really stretched out? Personally I don't like flat bars because to me they put your hands and wrists in the wrong position for the entire ride. If I didn't have drops, I'd at least go for a cruiser style bar. Bullhorn bars or butterfly bars might be a better choice still or even a mustache bar. Anything would be better than the simple flat bar to me whether it has a rise or not.

But you are correct, the stem and design of the Canyon might hamper your choices with doing much. So that's another reason I suggest send it back if you can.