Cannot Resize UI; Manual Edits do not Save

[TyrannusRex]

My machine's resolution is 1920x1080, and I cannot resize the game's UI. I'd just like to make the buttons a bit bigger and have the menu fill a tad more of the screen, but not only is the option to resize greyed out, but whenever I go into the AppOptions file to manually alter the upscaling, it always reverts back to default when I start the game, no matter what. I greatly appreciate any help can be provided!