Problems with MuseScore on linux

Hi,
first of all big thanks for making MuseScore - I am myself open-source developer and you really have created a wonderful product that brings music editing to everybody what is awesome.

My windows laptop is broken. I am now working on a linux machine that I also have. The appimage you provide on your donwload section is not working at all on my linux mint:
$ ./MuseScore-4.2.1.240230938-x86_64.AppImage
/usr/lib/x86_64-linux-gnu/libjack.so.0
/usr/lib/x86_64-linux-gnu/libnss3.so
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libpthread.so.0: version GLIBC_2.30' not found (required by /tmp/.mount_MuseScOZcZuI/bin/mscore4portable)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libm.so.6: versionGLIBC_2.29' not found (required by /tmp/.mount_MuseScOZcZuI/bin/mscore4portable)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version GLIBCXX_3.4.26' not found (required by /tmp/.mount_MuseScOZcZuI/bin/mscore4portable)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libm.so.6: versionGLIBC_2.29' not found (required by /tmp/.mount_MuseScOZcZuI/bin/../lib/libsndfile.so.1)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libm.so.6: version GLIBC_2.29' not found (required by /tmp/.mount_MuseScOZcZuI/bin/../lib/libFLAC.so.8)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libc.so.6: versionGLIBC_2.28' not found (required by /tmp/.mount_MuseScOZcZuI/bin/../lib/libsystemd.so.0)
/tmp/.mount_MuseScOZcZuI/bin/mscore4portable: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.30' not found (required by /tmp/.mount_MuseScOZcZuI/bin/../lib/libsystemd.so.0)

So I used the Software Manager and installed MuseScore from there. This technically installed MuseScore 4.2.1 as flatpack. The first problem I had was that my scores have been on a different volume and I could not access them from the MuseScore file-chooser as this folder was not shown even though it was there. I studied some details about flatpack and figured out how I can grant permission to that mount/volume and made this working.

Now I wanted to install a special plugin.
I followed your instructions on https://musescore.org/en/handbook/4/plugins
Also I verified my preferences and in the folder section it says my plugins folder is at
/home/joerg/Documents/MuseScore4/Plugins

So the plugins compatible for musescore 4 are in this folder but musescore is not showing any of them. I tried reload plugins and all kind of variants folder per plugin with the qml file in there or all qml files directly in the /home/joerg/Documents/MuseScore4/Plugins folder - nothing helps.

What I could figure out is that the plugins listed in musescore are physically on my disc in the folder
/var/lib/flatpak/app/org.musescore.MuseScore/current/active/files/share/mscore-4.2/plugins/

However, I cannot write to this folder. So I used sudo to copy the plugins to this folder with root permissions.
Then I hit "reload plugins" in MuseScore and again nothing changed.

When I restarted MuseScore the next time, the plugin was listed and I could enable and finally use it.
However, this was a complex journey full of pitfalls and I am a computer scientist so I do not give up easily with such problems. Most users of MuseScore are maybe not that skilled with IT but rather want to focus on music instead. So maybe my posting could help other Linux users with similar problems.
Also it would be really cool, if you could use the feedback to improve your plugin installation documentation.
Maybe also my error with your AppImage can help to identify and potentially fix problems.

Thanks again for making your great product MuseScore freely available and brining more music and hopefully peace to this planet :)
Kind regards
Jörg