Having upgraded to Leap 15.6 I get a similar message to the one in https://forums.opensuse.org/t/akonadi-dienst-lauft-nicht/141196 but am not clear what the solution is.
QStandardPaths: runtime directory ‘/run/user/1000’ is not owned by UID 0, but a directory permissions 0700 owned by UID 1000 GID 100
D-Bus session bus is not available!
Why are you running this program as root?
Because I got a similar fault when running as user. When running as user I get the same remark about dbus a few more lines after:
org.kde.pim.akonadiserver: Database process exited unexpectedly during initial connection!
org.kde.pim.akonadiserver: executable: "/usr/sbin/mysqld"
org.kde.pim.akonadiserver: arguments: ("--defaults-file=/home/john/.local/share/akonadi/mysql.conf", "--datadir=/home/john/.local/share/akonadi/db_data/", "--socket=/run/user/1000/akonadi/mysql.socket", "--pid-file=/run/user/1000/akonadi/mysql.pid")
This thread is closed as further investigation suggests that the problem may be related to file corruption.