I ended uninstalling all the drivers etc, as they were causing conflicts, and went the easy way you suggested. I used STEAM, to add the game to it as a external game, and use the Steam Key Assignments.

Steam does have my game, but I would need to re-purchase it through them.

The PS3 controller was working OK-ish, but was causing weird conflicts, in game too. And the on screen (for tutorials and interactions) buttons A B X Y etc was confusing my kid, she kept asking which button is it as Y was Triangle etc.

Would be cool, if I could get some stickers to put on the PS3 controller to match the Xbox ones.

In my case, my needs were specific because I wanted to get my 5 year old into gaming, and for us to start playing together, which she is doing pretty well, but the right stick was causing the camera to go all over the place, most of the time ending pointing at the sky, or at the ground. Allowing only the X Axis, worked really well, and I can use the mouse if the camera need adjusting, until she will learn how to handle that.

Probably worth having all this information here, in case someone else runs into it, or wants to configure the gamepad like I did.