You will need to download and install an application called DS4Windows. If you already use your Dualsense controller for other games, I'm sure you are already familiar with it.

The link for this application is: https://ds4-windows.com/download/ryochan7-ds4windows/

Install all of the drivers that the website asks, or the application will not work properly.

Download and install the ViGEmBus driver and the HidHide drivers during the setup. Your PC will need to restart to complete the installation. If you already have DS4Windows installed, go to the settings tab, under "Util" there is an option called "controller/driver setup." Step 4 is the HidHide driver.

This is what the application will look like when you boot it up and connect your controller:

This part is pretty straightforward. Go to Ultimate Alliance in your library, right click on it and go to Properties>Controllers and disable steam input.

Once you have completed the above steps, you must hide your Dualsense controller using the HidHide application from earlier. First, connect your controller and open DS4Windows. Your controller should show up and be connected. The problem, however, is that now your computer and MUA will detect two controllers at the same time. MUA being a co-op game, will try to force you to do co-op every time you hit the pause menu. To prevent this, you must hide the Dualsense in HidHide.

It is critical that you open and connect your controller in DS4Windows first or else it will not detect your controller at all. Then you can open HidHide, go to the devices tab, check the "Sony Interactive Entertainment Wireless Controller", and check the "Enable Device Hiding" box down below.

You will need to open DS4Windows and HidHide every time you want to play, but no buttons will be broken or misconfigured and there will be no double input. This is the best way I have found to play the game. I hope this was helpful. Enjoy!