Update broke KDE wayland login (Slowroll)

Ok, I note the following repeating error messages through the log you shared…

Sep 11 19:26:34 localhost.localdomain kwin_wayland[5712]: kwin_wayland_drm: drmSetClientCap for Atomic Mode Setting failed. Using legacy mode on GPU "/dev/dri/card0"
Sep 11 19:26:35 localhost.localdomain kwin_wayland[5712]: could not create a component for  "org.kde.spectacle.desktop"
Sep 11 19:26:36 localhost.localdomain kernel: kwin_wayland[5712]: segfault at 0 ip 0000000000000000 sp 00007ffe39bac358 error 14 likely on CPU 2 (core 2, socket 1)
Sep 11 19:26:36 localhost.localdomain systemd-coredump[5802]: Process 5712 (kwin_wayland) of user 1000 terminated abnormally with signal 11/SEGV, processing...
Sep 11 19:26:36 localhost.localdomain systemd-coredump[5803]: Process 5712 (kwin_wayland) of user 1000 dumped core.

You have AMD graphics using the radeon driver…

  Device-1: Advanced Micro Devices [AMD/ATI] Kaveri [Radeon R7 Graphics]
    driver: radeon v: kernel
  Display: x11 server: X.Org v: 21.1.12 with: Xwayland v: 24.1.2 driver: X:
    loaded: modesetting unloaded: fbdev,vesa dri: radeonsi gpu: radeon
    resolution: 1: 1920x1080~60Hz 2: 1920x1080~60Hz

FWIW, there was a thread concerning AMD and Plasma Wayland problems…

…but I’m not familiar with AMD graphics and yours is a different generation…not sure if the workaround is applicable.

Perhaps @mrmazda could chime in here.