The PC port of Dragon Ball Z: Kakarot is not really as expected, and rightly: many players are currently stuck with a locked resolution of 1920x1080. However, user Steam WhySoAngry has posted a few tips, which will surely help to solve your problem. You can find a summary of his post on the Steam forums below.
From 1080p to 1440p or 4k
- Make sure that your screen resolution on Windows is set to maximum. The game setting will never be able to go to a higher resolution than your desktop resolution.
- Increase the maximum resolution in your Nvidia/AMD panel, this will force the game resolution if necessary.
- In DBZ Kakarot settings, increase the internal resolution: 100 = 1080p, 150 = 1440p, 200 = 4K.
Nvidia cards only
- Enter the Nvidia control panel
- Go to 3D settings management
- In the general settings, search for DSR - factors
- Check X2 and X4
While waiting for a patch, this might be a good help if you want to explore the world of Goku.