I recently upgraded from a 1080p monitor to a 1440p one and I noticed this game still opens at 1080p (I know the actual game resolution is probably 800x600 stretched)

For most GOG games you just modify the dosbox_DF.conf file but Rebellion doesn't use dosbox.

Does anyone know how to do this? I normally wouldn't really care but at 1080p the monitor flickers in these older games (and it just plain looks way better at 1440p even with a stretched 800x600 render resolution). Changing the resolution from 1080p to 1440p has fixed this for all my other GOG games.

Edit: I solved the issue, in the nVidia control panel, under 'Adjust desktop size and position' I had to change scaling from 'Display' to 'GPU'. I'm guessing it's the monitor that decides to run 800x600 or 1024x768 at 1080p instead of 1440p.