What I'm asking about is that I have gotten Star Wars Galactic Battlefront Saga working using the mods from Expanded Fronts. I can run it at 1920x1080 in windowed mode and it does run just right with one caveat. The game has to run within a windowed frame. What is happening is that there is a small offset so that I can't get at the bottom and the right side of the screen. The only way it runs properly is in windowed mode.
I'm running Manjaro (X and sddm). On the image below, please pay attention to the top left corner for a good example of what I'm talking about. I'm hoping that there are a couple of X tweaks that I can use to 1) center the window with the window borders hiding outside the active screen and 2) bring it on top of all of the other windows.