@JKSH Seems you were correct :
QML debugging is enabled. Only use this in a safe environment. Info: Starting QML Puppet ((null):0, (null)) Info: Could not load the Qt platform plugin "xcb" in "" even though it was found. ((null):0, (null)) Fatal: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem. Available platform plugins are: wayland, offscreen, minimal, wayland-egl, xcb, linuxfb, minimalegl, vnc, vkkhrdisplay, eglfs. ((null):0, (null))ldd returns :
linux-vdso.so.1 (0x00007ffed5dfb000) libQt6XcbQpa.so.6 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libQt6XcbQpa.so.6 (0x00007f3bda977000) libxkbcommon-x11.so.0 => /lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007f3bda955000) libxkbcommon.so.0 => /lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007f3bda90f000) libxcb-cursor.so.0 => not found libxcb-icccm.so.4 => /lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007f3bda908000) libxcb-image.so.0 => /lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007f3bda900000) libxcb-keysyms.so.1 => /lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007f3bda8fb000) libxcb-randr.so.0 => /lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007f3bda8e9000) libxcb-render-util.so.0 => /lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007f3bda8e2000) libxcb-shm.so.0 => /lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007f3bda8dd000) libxcb-sync.so.1 => /lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007f3bda8d4000) libxcb-xfixes.so.0 => /lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007f3bda8c9000) libxcb-render.so.0 => /lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007f3bda8bb000) libxcb-shape.so.0 => /lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007f3bda8b6000) libxcb-xkb.so.1 => /lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007f3bda898000) libxcb.so.1 => /lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f3bda86e000) libQt6OpenGL.so.6 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libQt6OpenGL.so.6 (0x00007f3bda7cc000) libQt6Gui.so.6 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libQt6Gui.so.6 (0x00007f3bd9e00000) libGL.so.1 => /lib/x86_64-linux-gnu/libGL.so.1 (0x00007f3bd9d79000) libQt6Core.so.6 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libQt6Core.so.6 (0x00007f3bd9600000) libX11-xcb.so.1 => /lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f3bda7c5000) libX11.so.6 => /lib/x86_64-linux-gnu/libX11.so.6 (0x00007f3bd94c2000) libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f3bd9d72000) libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f3bd9d6d000) libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f3bd9200000) libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f3bd9117000) libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f3bd9d49000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f3bd8e00000) libxcb-cursor.so.0 => not found libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f3bd8cb9000) libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f3bd9d42000) libxcb-util.so.1 => /lib/x86_64-linux-gnu/libxcb-util.so.1 (0x00007f3bd9d39000) libXau.so.6 => /lib/x86_64-linux-gnu/libXau.so.6 (0x00007f3bd9d33000) libXdmcp.so.6 => /lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f3bd9d29000) libEGL.so.1 => /lib/x86_64-linux-gnu/libEGL.so.1 (0x00007f3bd9d16000) libfontconfig.so.1 => /lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007f3bd9cc8000) libQt6DBus.so.6 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libQt6DBus.so.6 (0x00007f3bd9051000) libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f3bd9caa000) libfreetype.so.6 => /lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f3bd8bef000) libGLdispatch.so.0 => /lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f3bd8b37000) libGLX.so.0 => /lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f3bd9490000) libicui18n.so.56 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libicui18n.so.56 (0x00007f3bd8600000) libicuuc.so.56 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libicuuc.so.56 (0x00007f3bd8200000) libicudata.so.56 => /home/user/Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/plugins/platforms/./../../lib/libicudata.so.56 (0x00007f3bd6800000) librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f3bd9ca1000) /lib64/ld-linux-x86-64.so.2 (0x00007f3bdaa32000) libpcre2-8.so.0 => /lib/x86_64-linux-gnu/libpcre2-8.so.0 (0x00007f3bd8a9d000) libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f3bd9c8c000) libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f3bd9026000) libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f3bd67b2000) libpng16.so.16 => /lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f3bd85c8000) libbrotlidec.so.1 => /lib/x86_64-linux-gnu/libbrotlidec.so.1 (0x00007f3bd9483000) libmd.so.0 => /lib/x86_64-linux-gnu/libmd.so.0 (0x00007f3bd9476000) libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f3bd66e2000) libbrotlicommon.so.1 => /lib/x86_64-linux-gnu/libbrotlicommon.so.1 (0x00007f3bd66bf000) libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007f3bd901a000) libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f3bd6577000) liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f3bd6545000) libzstd.so.1 => /lib/x86_64-linux-gnu/libzstd.so.1 (0x00007f3bd6491000) liblz4.so.1 => /lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f3bd646e000) libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f3bd6448000)I installed libxcb-cursor and the problem is solved, thanks a lot !