Re: Legality and banning concerns
I think it should be okay to modify game config files because they can disable any command or any config file whenever they want. But no one can guarantee that you will not get banned for that. But I don't think no one ever got banned for modifying the config files. I believe gdolphn using game configs for super glide (same button for jump and crouch) and he never got banned for that.
But I would never risk using external software such as razer synapse, steelseries gg or even steam config for keybinds or macros. They ban people for appropriate Steam names so they can also ban people for appropriate steam configs.