I have been able to reproduce this issue on both my steam deck, and my Laptop (Running Win 11) using a steam controller.
The reason why this is such a big problem is it makes using a steam deck less viable, as it forces players to either make do with the inferior aiming of the controller controls and get access to the very well done controller inputs of the game OR spend the time and effort required to set up a viable set of keyboard mouse controls on the deck and not have access to certain controls that are available to the controller scheme