My last update has left me with black screen and had to switch to Plasma X11

Hi Dean,
Sorry about that, I have no idea why this happened. Going forward here is the output from your original zypper command:-

alastair@HP-Z640-1:~> zypper se -si Mesa | grep -E "Mesa|Repository"
S  | Name                      | Type    | Version             | Arch   | Repository
i  | Mesa                      | package | 25.2.4-1699.2.pm.2  | x86_64 | (System Packages)
i  | Mesa-demo-egl             | package | 9.0.0-6.1           | x86_64 | Main Repository (OSS)
i  | Mesa-demo-x               | package | 9.0.0-6.1           | x86_64 | Main Repository (OSS)
i  | Mesa-dri                  | package | 25.2.4-1699.2.pm.13 | x86_64 | (System Packages)
i  | Mesa-libEGL1              | package | 25.2.4-1699.2.pm.2  | x86_64 | (System Packages)
i  | Mesa-libGL1               | package | 25.2.4-1699.2.pm.2  | x86_64 | (System Packages)
i  | Mesa-libva                | package | 25.2.4-1699.2.pm.13 | x86_64 | (System Packages)
i  | Mesa-vulkan-device-select | package | 25.2.4-1699.2.pm.13 | x86_64 | (System Packages)

There was also a question concerning gdm and this is what I have on this:-

alastair@HP-Z640-1:~> cat /etc/sysconfig/displaymanager | grep DISPLAYMANAGER=
alastair@HP-Z640-1:~> sudo cat /etc/sysconfig/displaymanager | grep DISPLAYMANAGER=
[sudo] password for root: 
alastair@HP-Z640-1:~> ps -e | grep dm
    687 ?        00:00:00 kworker/R-amdgpu_dm_hpd_rx_offload_wq
    688 ?        00:00:00 kworker/R-amdgpu_dm_hpd_rx_offload_wq
    689 ?        00:00:00 kworker/R-amdgpu_dm_hpd_rx_offload_wq
    690 ?        00:00:00 kworker/R-amdgpu_dm_hpd_rx_offload_wq
    691 ?        00:00:00 kworker/R-dm_vblank_control_workqueue
    716 ?        00:00:00 kworker/R-sdma0
    717 ?        00:00:00 kworker/R-sdma1
   2270 ?        00:00:00 rpc.idmapd
   2311 ?        00:00:00 gdm
   4265 ?        00:00:00 gdm-session-wor
   4998 tty2     00:00:00 gdm-wayland-ses
   6763 ?        00:00:00 kworker/R-kdmflush/254:0
   6766 ?        00:00:00 dmcrypt_write/254:0
   6779 ?        00:00:00 jbd2/dm-0-8
  15976 ?        00:00:00 kworker/u96:1-sdma0
alastair@HP-Z640-1:~> systemctl status display-manager.service
● display-manager-legacy.service - X Display Manager
     Loaded: loaded (/usr/lib/systemd/system/display-manager-legacy.service; enabled; preset: enabled)
     Active: active (running) since Thu 2025-10-23 08:43:35 BST; 1h 8min ago
 Invocation: 437fa482c377435ba23dd5705d9cbea3
    Process: 2295 ExecStart=/usr/lib/X11/display-manager start (code=exited, status=0/SUCCESS)
   Main PID: 2311 (gdm)
      Tasks: 5 (limit: 76927)
        CPU: 371ms
     CGroup: /system.slice/display-manager-legacy.service
             └─2311 /usr/sbin/gdm

Edit by Sauerland: Code-Tags