I found a solution that worked on two PC's. First is create a launch argument of "-popupwindow" which makes it borderless windowed, but to get it to fill the screen I had to change my screen resolution to one step down, which is very odd.

On my laptop with a 2560x1440 I went down to 1920x1080 and it worked great, but on my handheld pc I had to change from default screen res 1920x1080 down to 1600x900. Really odd and sucks to change that resolution but in the end it's better than windowed.