Linux app does not synchronize (flatpak's and permissions)

Operating system

Linux

Joplin version

3.0.15

Desktop version info

Joplin 3.0.15 (prod, linux)

Client-ID: f1c4d89fb7df4208853344f1beed1a93
Sync-Version: 3
Profil-Version: 47
Unterstützter Schlüsselbund: Nein

Sync target

File system

What issue do you have?

Hello everyone,
I am in the process of switching from Windows to Linux Manjaro and have set up a folder for synchronizing Joplin via the FritzBox. Under Windows, changes are also saved in this folder, but under Linux it doesn't work somehow, the text changes made in the notes are not saved in the folder. However, according to Joplin, synchronization is successful and no error message is displayed.
I came across the following post in the forum and think I have the same problem and would like to try the solution from doobes, but I don't know where and how to set the read and write permissions for all users in Linux?

The file open portals are likely interfering with the sync. You'll need to give the Flatpak direct access to the location the network drive is mounted.

You can either give acccess to your entire drive and all attached drives (not bypassing normal usergroups) with:

flatpak override --filesystem=host net.cozic.joplin_desktop

Or be more targetted, e.g:

flatpak override --filesystem=/media net.cozic.joplin_desktop