With that in mind, here’s how to remap the buttons on your gamepad through Steam. You can still use different mappings for each game, you just can’t use different mappings for different controllers.
So, when you adjust the button remapping settings for one Xinput controller, you’re adjusting them for all Xinput controllers on the system. All Xinput controllers-including Xbox controllers-will share the same button mapping settings because they don’t provide a way to uniquely identify different controllers to Steam.