If you want to SAVE YOUR CHANGED MAPPINGS DIRECTLY TO CONFIG without writing an extensive save function, it is very easily done like so:
If you have for example multiple players or users or characters on the same game, then you need a save function,
I haven’t researched how this functions in a packaged game, other than it works. Does it change the defaultinput.ini or does it create an Input.ini under /Saved/? If anyone knows, would be interesting. Some people have reported that reverting to default does NOT work in packaged games.