Ubuntu 22.04 LTS: Touchscreen calibration not working

I have taken over the task of getting the touchscreen to properly calibrate from Michael.

We use a monolithic xorg.conf, so putting the calibration data into /etc/X11/xorg.conf.d/99-calibration.conf would not work.

We have tried:

MatchProduct "PenMount TouchScreen"

as well as

MatchUSBID "14e1:6000"

without any change in behavior. The data xinput_calibrator collects just seems wrong; the first and the last 100 lines remain unreachable via touchscreen. Manually changing the MinY and MaxY values does not seem to change anything, either.

Help!

Our current configuration:

Section "InputClass"
        Identifier      "calibration"
        MatchProduct    "PenMount TouchScreen"
        #Option "MinX"  "519"
        #Option "MaxX"  "3623"
        #Option "MinY"  "467"
        #Option "MaxY"  "3577"
        Option  "MinX"  "519"
        Option  "MaxX"  "3623"
        Option  "MinY"  "100"
        Option  "MaxY"  "3900"
        Option  "SwapXY"        "0" # unless it was already set to 1
        Option  "InvertX"       "0"  # unless it was already set
        Option  "InvertY"       "0"  # unless it was already set
EndSection