X recognises a non-existent screen

[Yotam Benshalom]

I have one monitor only. However, x11 recognises two screens, and places one of them to the right of my real screen.
This causes several issues: I can "lose" my mouse pointer at the right hand side of my real screen. Some apps start on the non-existent screen, and it is hard or impossible (in case of some steam games) to pull them out to my real screen.
Gnome settings shows the two screens, my real screen first and the non-existent one second, but does not let me fiddle with the settings of the second one. It seems that xrandr sees this screen too:

~$ xrandr -q
Screen 0: minimum 8 x 8, current 7680 x 2160, maximum 32767 x 32767
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
   3840x2160 60.00*+ 30.00
   2560x1440 59.95
   1920x1080 60.00 59.94
   1600x900 60.00
   1280x1024 60.02
   1280x800 59.81
   1280x720 60.00 59.94
   1152x864 59.96
   1024x768 60.00
   800x600 60.32
   720x480 59.94
   640x480 59.94 59.93
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
None-1-1 connected (normal left inverted right x axis y axis)
   3840x2160 60.00 +

But trying to remove "None-1-1" yields an error:

~$ xrandr --output None-1-1 --off
X Error of failed request: BadMatch (invalid parameter attributes)
  Major opcode of failed request: 140 (RANDR)
  Minor opcode of failed request: 7 (RRSetScreenSize)
  Serial number of failed request: 45
  Current serial number in output stream: 47

Here is the content of /sys/class/drm, but I don't know what to make of it.

card0 card1 card1-DP-2 card1-HDMI-A-2 version
card0-Unknown-1 card1-DP-1 card1-HDMI-A-1 renderD128

I use an right-to-left environment, and maybe this is related.

ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: x11-xserver-utils 7.7+10build2
ProcVersionSignature: Ubuntu 6.8.0-22.22-generic 6.8.1
Uname: Linux 6.8.0-22-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
.proc.driver.nvidia.capabilities.fabric-imex-mgmt:
 DeviceFileMinor: 4323
 DeviceFileMode: 256
 DeviceFileModify: 1
.proc.driver.nvidia.capabilities.gpu0: Error: path was not a regular file.
.proc.driver.nvidia.capabilities.mig: Error: path was not a regular file.
.proc.driver.nvidia.gpus.0000.01.00.0: Error: path was not a regular file.
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.suspend: suspend hibernate resume
.proc.driver.nvidia.suspend_depth: default modeset uvm
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 550.67 Tue Mar 12 23:54:15 UTC 2024
 GCC version: gcc version 13.2.0 (Ubuntu 13.2.0-23ubuntu3)
ApportVersion: 2.28.0-0ubuntu1
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: pass
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Sat Apr 13 20:18:55 2024
DistUpgraded: 2024-01-19 13:45:35,307 DEBUG migrateToDeb822Sources()
DistroCodename: noble
DistroVariant: ubuntu
DkmsStatus:
 nvidia/550.67, 6.8.0-11-generic, x86_64: installed
 nvidia/550.67, 6.8.0-22-generic, x86_64: installed
GraphicsCard:
 NVIDIA Corporation GA104 [GeForce RTX 3070 Ti] [10de:2482] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Gigabyte Technology Co., Ltd GA104 [GeForce RTX 3070 Ti] [1458:408f]
InstallationDate: Installed on 2022-01-31 (803 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Alpha amd64 (20220126)
MachineType: ASUS System Product Name
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.8.0-22-generic root=UUID=06eb0295-6f5f-4d0e-96e7-4d2e2fe687ac ro quiet splash vt.handoff=7
SourcePackage: x11-xserver-utils
UpgradeStatus: Upgraded to noble on 2024-01-19 (85 days ago)
dmi.bios.date: 03/18/2024
dmi.bios.release: 34.1
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3401
dmi.board.asset.tag: Default string
dmi.board.name: PRIME Z690-A
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr3401:bd03/18/2024:br34.1:svnASUS:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnPRIMEZ690-A:rvrRev1.xx:cvnDefaultstring:ct3:cvrDefaultstring:skuSKU:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.sku: SKU
dmi.product.version: System Version
dmi.sys.vendor: ASUS
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.120-2
version.libgl1-mesa-dri: libgl1-mesa-dri 24.0.3-1ubuntu4
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:21.1.11-2ubuntu1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:22.0.0-1build1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20210115-1build1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-2build1