Segfault in libQt6Quick.so.6.9.1

[linux-aarhus]

I have seen a couple of topic with roughly the same description

@dano

System:
  Kernel: 6.12.34-1-MANJARO arch: x86_64 bits: 64 compiler: gcc v: 15.1.1
    clocksource: tsc avail: hpet,acpi_pm
    parameters: BOOT_IMAGE=/boot/vmlinuz-x86_64 lang=en_US keytable=de tz=UTC
    misobasedir=manjaro misolabel=MANJARO_KDE_2504 quiet systemd.show_status=1
    splash driver=free nouveau.modeset=1 i915.modeset=1 radeon.modeset=1

I specifically note that the system info is generated while using a Manjaro installation ISO - so it is difficult to conclude anything from this - other than your system work.

@dano

When loading the session KDE starts switching off/on for couple of times until the screen is completely black

From your system info I looked for and found

Graphics:
  Device-1: NVIDIA GA106 [GeForce RTX 3060 Lite Hash Rate]
    vendor: Micro-Star MSI driver: nouveau v: kernel non-free: 550-570.xx+

Please check what Nvidia recommends for your specific GPU by using the utilities

nvidia-driver-assistant

or

nvidia-recommended-driver

The latter is simply a wrapper around the former and will give you a single clue.

See this for instruction on how to chroot your system [root tip] [recovery] Basic Manjaro Linux Recovery

When you have succesfully entered the chroot environment - please install the driver recommended by the above utility.