SELinux by default doesnt allow remote clients to access the contents of a shared folder due to its default configuration. The way Fedora and probably other SELinux distros handle this is very counter intuitive. (https://docs.fedoraproject.org/en-US/quick-docs/samba/#sharing_a_directory_inside_home)
A solution could be to add a warning within KDE, that the user has to write its own SELinux policy for the file share to work, or even create this policy for the user automatically. I know that this issue is especially Fedora related, but a UI warning would need to be implemented in KDE, therefore this request.