Community Manager@evanadley Just to add it is a great game and will keep you busy for a while.
Fred is right, there isn't really any controller support because the game was based more on a mouse and keyboard than a controller.
However, when I play on a PC (Through Game Pass), I use a wired Xbox Elite controller. I am not personally big on mouse and keyboard. With a PC though, not all are the same. The amount of programs, security, files, and folders on each PC can cause issues for some and not for others.
Everyone runs into issues with the controller so when it does occur, there are tons of threads on the game and controllers and getting them to work.
When it comes to Steam Deck though, we don't support this much past the basic troubleshooting the Deck has, so it is a trial-and-error thing with this platform.
I did see a video of someone playing the game on Steam Deck using the right touch pad to simulate a mouse (you can also do this with a DualShock 4 or DualSense when playing docked). It looks manageable, but the player needed a lot of time to do everything. Luckily the game has a pause button.
Dragon Age II might be easier because of the "awesome button" (default R on keyboards) which targets the nearest enemy or other interactable item.
