Unfortunately, I discovered that all the previous measures and assumptions regarding the display rotation issue were incorrect. The problem is caused by a default configuration in KDE, specifically the “autoRotation” option, which is set to “tabletMode.” This means that KWin only rotates the screen when it receives the “tabletModeChanged” signal from DBUS. Unfortunately, this signal isn’t always reliable, which causes the display to work sporadically and sometimes not at all. It is possible to manually disable the option in the display settings. Once the option is disabled, the screen will always rotate—even in notebook mode—when you tilt the device. Display rotation works reliably in this mode.

I am working on a solution so that manual switching is no longer necessary and it works immediately when Kader⁴² is installed or when the kader42-convertible-tools package is updated.