Install Musescore 4 on Debian 11

I appear to have successfully installed this on my old (Samsung Netbook) laptop. From the command line, it tells me that Musescore has been installed in the appropriate folder and the MuseScore4Portable icon appears in the list of applications, but double-clicking the icon just produces the "waiting" spinning icon, which then stops without the program running. I have also used both the command line (chmod) and r-clicking the AppImage icon to go into permissions and tick the appropriate box, but neither helps. I have previously had some help in this forum but sadly nothing so far has worked. I would really appreciate any suggestions!