in Screengrab Hyperion Windows its Adapter 0 Monitor 0 > did you try that?
Thanks for your answers, but I tried everything
Danny80 Sorry, seems I mixed the platforms. Ambientheater77 is right. On Windows you can grab each Monitor separately with QT. On Ubuntu i would need to check, but because QT is using underlying X11, I assume you get the X11 screen which cuts across two monitors.
After resetting and reinstalling everything with no luck, I came to a solution after playing around with the Grabber-CLI-Tools (hyperion-x11, hyperion-qt, ....). I crop the screen on the left by 1920px and at the bottom by 480px. This will cut out the whole left Display and the bottom of the second one, because of different resolutions. The screenshot was alwas expanded to the height of the larger display (the monitor) and added the two display widths together (3200x1200 overall). This is not the perfect solution, but it works. If the display is not connected, for example the calculation willl cause an error. Maybe I will write a script for calculating and changing these values dynamically.