It got solved, apparantly I needed to change the “FULLSCREEN” setting back and forth a few times and then suddenly it worked and 1920x1080 was available.
Somehow when I launch game today the resolution cant exceed 1280x720 which is shown as “100%”. But my desktop resolution is 1920x1080 which is also my monitors native resolution.
It worked fine the last time I played some months ago and I made no changes to the game since I tried starting it today. So I really have no idea why this is happening.
How do I fix this? How to make resolution 1920x1080 available for Boundless again?!?
Thanks for any help!