Windows in parallels not being able to use the full 5120x2160 resolution of my LG p40w-20

Hi!
Parallels on my MacBook Pro 16" M1 Max won't work properly when I try to make it full screen on my LG p40w-20. It will only use like 80% of the screen at maximum, and then also the mouse cursor will be skewed away from where I see it on the screen. In order to click on an app, I might have to move the cursor like 5cm away from where it actually is and click there in order to open the app.

When I use the parallel window in NOT fullscreen mode, it will max out at covering about 80% of the screen as well. The cursor will work fine though.

Is this a known problem, or do you guys have an idea on how to solve it?