The game auto detects whether you’re playing with a controller, or a mouse and keyboard to change the Heads up display “HUD”. This feature prevents you from customizing a gamepad that has more buttons than an xbox controller. When assigning keyboard presses to the controller the system changes the HUD to “keyboard” and stops reading the controller joystick inputs during the HUD swap. Being able to toggle off this feature, and just lock the HUD to controller or Keyboard/mouse should allow the keyboard and controller to be used together without input lag switching over the HUD.
More games should definitely support hybrid inputs for the growing number of controllers that have extra buttons/gyro functions. And the existence of steam input that allows people to bind complicated setups to even their basic controllers. I also have such a controller with extra buttons and I know the pain of getting games to play nice with them well. But sadly the lag you are talking about isn’t necessarily from the HUD dynamically changing and even if such an option existed it likely wouldn’t solve the quirk.
There’s games out there that let you choose static controller/keyboard prompts that still lag when swapping inputs, there’s games out there that don’t let you choose static prompts but don’t lag when swapping inputs, meaning you just get the HUD flickering between prompts with seamless gameplay.
It’s entirely about how the game reads inputs, but I agree that it would be nice to both have an option to lock the style of prompts and the game handle mixed inputs better.