Systemd D-Bus not being started for user

[Ragadabing]

Hello,
I've installed Arch Linux on my Raspberry Pi 4 and connect via SSH to it. I'd like to start some user systemd services, but somehow I can't because something with the bus service is broken. I've looked through this forum and several github issues, but nothing seemed to work for me. Here is the result of the various command I've executed so far (the result for all the environment variables was empty):

$this->bbcode_second_pass_code('', '
$ systemctl --user status
Failed to connect to bus: No such file or directory
')
$this->bbcode_second_pass_code('', '
$echo $XDG_RUNTIME_DIR
')
$this->bbcode_second_pass_code('', '
$echo $DBUS_SESSION_BUS_ADDRESS
')
$this->bbcode_second_pass_code('', '
$ echo $DBUS_SESSION_BUS_PID
')
$this->bbcode_second_pass_code('', '
$ systemctl --user set-environment
Too few arguments.
')
$this->bbcode_second_pass_code('', '
$ systemctl --user import-environment
Failed to connect to bus: No such file or directory
')
$this->bbcode_second_pass_code('', '
$ dbus-update-activation-environment --systemd --all
dbus-update-activation-environment: error: unable to connect to D-Bus: Using X11 for dbus-daemon autolaunch was disabled at compile time, set your DBUS_SESSION_BUS_ADDRESS instead
')
$this->bbcode_second_pass_code('', '
$ systemctl --user show-environment
Failed to connect to bus: No such file or directory
')
$this->bbcode_second_pass_code('', '
# systemctl status systemd-logind.service
● systemd-logind.service - Login Service
Loaded: loaded (/usr/lib/systemd/system/systemd-logind.service; static; vendor preset: disabled)
Active: active (running) since Sat 2020-02-15 15:50:56 UTC; 16min ago
Docs: man:systemd-logind.service(8)
man:logind.conf(5)
https://www.freedesktop.org/wiki/Software/systemd/logind
https://www.freedesktop.org/wiki/Software/systemd/multiseat
Process: 2849 ExecStartPre=/sbin/modprobe -abq drm (code=exited, status=1/FAILURE)
Main PID: 2850 (systemd-logind)
Status: "Processing requests..."
Tasks: 1 (limit: 4915)
Memory: 1.1M
CGroup: /system.slice/systemd-logind.service
└─2850 /usr/lib/systemd/systemd-logind

Feb 15 15:50:56 rpi systemd[1]: Starting Login Service...
Feb 15 15:50:56 rpi systemd-logind[2850]: New seat seat0.
Feb 15 15:50:56 rpi systemd[1]: Started Login Service.
')
$this->bbcode_second_pass_code('', '
# systemctl status dbus.service
● dbus.service - D-Bus System Message Bus
Loaded: loaded (/usr/lib/systemd/system/dbus.service; static; vendor preset: disabled)
Active: active (running) since Mon 2020-01-27 20:06:22 UTC; 2 weeks 4 days ago
TriggeredBy: ● dbus.socket
Docs: man:dbus-daemon(1)
Main PID: 281 (dbus-daemon)
Tasks: 1 (limit: 4915)
Memory: 3.1M
CGroup: /system.slice/dbus.service
└─281 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only

Jan 27 20:06:22 rpi systemd[1]: Started D-Bus System Message Bus.
Feb 01 21:52:27 rpi dbus-daemon[281]: [system] Activating via systemd: service name='org.freedesktop.PolicyKit1' unit='polkit.service' requested by ':1.13' (uid=0 pid=283 comm="/usr/bin/python /usr/bin/firewalld>
Feb 01 21:52:27 rpi dbus-daemon[281]: [system] Successfully activated service 'org.freedesktop.PolicyKit1'
Feb 15 15:50:56 rpi dbus-daemon[281]: [system] Activating via systemd: service name='org.freedesktop.login1' unit='dbus-org.freedesktop.login1.service' requested by ':1.202' (uid=0 pid=2848 comm="loginctl enable>
Feb 15 15:50:56 rpi dbus-daemon[281]: [system] Successfully activated service 'org.freedesktop.login1'
')
$this->bbcode_second_pass_code('', '
# systemctl status dbus.socket
● dbus.socket - D-Bus System Message Bus Socket
Loaded: loaded (/usr/lib/systemd/system/dbus.socket; static; vendor preset: disabled)
Active: active (running) since Mon 2020-01-27 20:06:22 UTC; 2 weeks 4 days ago
Triggers: ● dbus.service
Listen: /run/dbus/system_bus_socket (Stream)
CGroup: /system.slice/dbus.socket

Jan 27 20:06:22 rpi systemd[1]: Listening on D-Bus System Message Bus Socket.
')

The only (partial) success I had was to manually start a dbus session using the following:
$this->bbcode_second_pass_code('', '
$ dbus-launch
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-B8QrmO2967,guid=d30f1ad4e6d99e8be2fa7e8d5e481881
DBUS_SESSION_BUS_PID=4669
$ export DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-B8QrmO2967,guid=d30f1ad4e6d99e8be2fa7e8d5e481881
$ export DBUS_SESSION_BUS_PID=4669
$ systemctl --user status
Failed to read server status: The name org.freedesktop.systemd1 was not provided by any .service files
$ systemctl --user show-environment
Failed to get environment: The name org.freedesktop.systemd1 was not provided by any .service files
')