Today's snap and kde-plasma-extras-6.0.5p0 starts on a T14 gen3 Intel,
I can click through the menu in the bottom left corner, but typing to
search/filter applications immediately crashes the menu, the background
becomes black/white again, X11 keeps running though.

First time starting KDE Plasma on this installation, i.e. no ~/.config/
or other files from previous attempts:

~/.config/kwinrc contains this as per package readme:
  [Compositing]
  Enabled=false

~/.xsession is this as per package readme:
  #!/bin/sh
  export XDG_RUNTIME_DIR=/tmp/run/$(id -u)
  if [ ! -d $XDG_RUNTIME_DIR ]; then
      mkdir -m 700 -p $XDG_RUNTIME_DIR
  fi
  export DESKTOP_SESSION=plasma
  export QT_FORCE_STDERR_LOGGING=1
  export QT_LOGGING_RULES="*=true"
  export XDG_CURRENT_DESKTOP=KDE
  /usr/local/bin/startplasma-x11 > ~/.startplasma-x11.log 2>&1

My user's processes left over after crash (first xenodm login after boot):
  81139 /usr/local/bin/redshift -v
  11425 /usr/local/libexec/geoclue-2.0/demos/agent
  12137 /usr/local/bin/plasma_session
  62274 /usr/local/bin/startplasma-x11
  46317 /bin/sh /home/kn/.xsession
  30331 /bin/sh /etc/X11/xenodm/Xsession

I think this means the window manager crashed and I do see
  -rw-------  1 kn  kn    7659136 Jun 12 15:05 kwin_x11.core
  -rw-------  1 kn  kn  309378920 Jun 12 15:04 plasmashell.core
  -rw-------  1 kn  kn  156135704 Jun 12 14:36 systemsettings.core

kwin_x11 backtrace:
  Program terminated with signal SIGABRT, Aborted.
  #0  0x00000bd34006d36b in _libc_fputws (ws=0x751b68b19d40 L"\002", fp=0x751b68b19ae4) at /usr/src/lib/libc/stdio/fputws.c:47
  47				FUNLOCKFILE(fp);
  [Current thread is 1 (process 193917)]
  #0  0x00000bd34006d36b in _libc_fputws (ws=0x751b68b19d40 L"\002", fp=0x751b68b19ae4) at /usr/src/lib/libc/stdio/fputws.c:47
  #1  0x00000bd3859a478d in qAbort() () from /usr/local/lib/libQt6Core.so.4.1
  #2  0x00000bd3859a7af5 in qt_message(QtMsgType, QMessageLogContext const&, char const*, __va_list_tag*) () from /usr/local/lib/libQt6Core.so.4.1
  #3  0x00000bd3859acfc2 in QMessageLogger::fatal(char const*, ...) const () from /usr/local/lib/libQt6Core.so.4.1
  #4  0x00000bd318177ec6 in init_platform(QString const&, QString const&, QString const&, int&, char**) () from /usr/local/lib/libQt6Gui.so.6.0
  #5  0x00000bd318175cac in QGuiApplicationPrivate::createPlatformIntegration() () from /usr/local/lib/libQt6Gui.so.6.0
  #6  0x00000bd31817819d in QGuiApplicationPrivate::createEventDispatcher() () from /usr/local/lib/libQt6Gui.so.6.0
  #7  0x00000bd385a1a180 in QCoreApplicationPrivate::init() () from /usr/local/lib/libQt6Core.so.4.1
  #8  0x00000bd31817190d in QGuiApplicationPrivate::init() () from /usr/local/lib/libQt6Gui.so.6.0
  #9  0x00000bd340cbeb2a in QApplicationPrivate::init() () from /usr/local/lib/libQt6Widgets.so.2.1
  #10 0x00000bd32a162d95 in KWin::Application::Application(KWin::Application::OperationMode, int&, char**) () from /usr/local/lib/libkwin.so.1.0
  #11 0x00000bd0968bf806 in main ()

The log file with debug output as per package readme is 224M...
Any idea where to start debugging?
Can someone else reproduce?