I've heard of another user having trouble with the Steelseries Nimbus on Mac, it seems like it is an issue with Unity - I think it has trouble detecting its pressure sensitive buttons. Unfortunately, there's little information about the issue online and I don't have the controller myself, so it might be a while before I can get a fix for that case. I'm sorry for the trouble right now.
What do you mean about the left analog stick on the PS4 controller?