ERROR: Unable to create GUI. Exiting in kodi-gbm

[Inocious]

I can't make gobi-gbm works under my ubuntu 22.04 server (In Proxmox under LXC container but it's unrelated probably).

Here the logs:

Apr 21 16:21:23 Kodi systemd[1]: Started Kodi standalone (GBM).
Apr 21 16:21:23 Kodi kodi-standalone[454]: ERROR: Unable to create GUI. Exiting
Apr 21 16:21:23 Kodi kodi-standalone[465]: ERROR: Unable to create GUI. Exiting
Apr 21 16:21:23 Kodi kodi-standalone[476]: ERROR: Unable to create GUI. Exiting
Apr 21 16:21:24 Kodi kodi-standalone[445]: /usr/bin/kodi --standalone  has exited in an unclean state 3 times in the last 1 seconds.
Apr 21 16:21:24 Kodi kodi-standalone[445]: Something is probably wrong
Apr 21 16:21:24 Kodi killall[482]: kodi.bin: no process found
Apr 21 16:21:24 Kodi systemd[1]: kodi-gbm.service: Control process exited, code=exited, status=1/FAILURE
Apr 21 16:21:24 Kodi systemd[1]: kodi-gbm.service: Failed with result 'exit-code'.

Here is my kodi:

root@Kodi:~# kodi -v
Kodi Media Center 20.2 (20.2.0) Git:20230630-5f418d0b13
Copyright (C) 2005-2021 Team Kodi - http://kodi.tv

And here all the lines I used from a clean install:

git clone https://github.com/graysky2/kodi-standalone-service.git
cd kodi-standalone-service
make install
systemd-sysusers
systemd-tmpfiles --create
mkdir /etc/sysusers.d/
cat <<EOF > /etc/sysusers.d/kodi-standalone.conf
# override these settings by copying this to /etc/sysusers.d/ and modifying it therein

# Type Name ID GECOS Home directory Shell
g kodi - -
u kodi - "Kodi User" /var/lib/kodi

# supplemental groups
m kodi audio
m kodi optical
m kodi video

# other groups, see: /usr/lib/sysusers.d/arch.conf or basic.conf
# m kodi network
# m kodi power
# m kodi tty
# m kodi disk
# m kodi storage

# Ubuntu users only
# uncomment the following line if the kodi user needs access to /etc/ttyxxxx
# https://github.com/graysky2/kodi-standalone-service/issues/14
m kodi dialout

# uncomment the following line if you're running Ubuntu >=20 since they created
# a new render group of which the kodi user needs to be a member
m kodi render
EOF
systemctl mask systemd-logind
pam-auth-update
systemctl enable kodi-gbm
reboot

Did I miss a step ? I have no desktop environment installed at all.

EDIT:
I have those logs in kodi:

2024-04-21 16:44:44.587 T:552     error <general>: DBus error: org.freedesktop.DBus.Error.ServiceUnknown - The name org.freedesktop.UPower was not provided by any .service files
2024-04-21 16:44:44.598 T:552   critical <general>: CApplication::CreateGUI - unable to init windowing system

I'm messing up some stuff probably.
I'm trying to avoid having any desktop environment like LXQt.
Do I have to get a display server like X11 or Wayland installed at least ?

I understood that GBM was enough for kodi-gbm. It's already installed on my Ubuntu server by default as I'm aware. So I probably miss something.