modify /usr/bin/startplasmamobile like this

startplasmamobile snip

if [ -d "/dev/dri" ]; then
        kwin_wayland --drm --xwayland plasma-phone 2>&1 | logger -t "$(whoami):plasma-mobile"
elif [ -d "/usr/lib/libhybris-egl" ]; then
        # export EGL_PLATFORM=hwcomposer
        # export QT_LOGGING_RULES="kwin*.debug=true;qt*.debug=true"
        export QT_LOGGING_RULES="kwin*.debug=true"
        export LD_PRELOAD=/usr/lib/libhybris-egl/libEGL.so.1
        kwin_wayland --hwcomposer /usr/bin/plasma-phone 2>&1 | logger -t "$(whoami):plasma-mobile"
else