Further to the post on Feb 19, 2026, newer versions of KWin are significantly more robust at handling internal display switching. However, system hangs still occur when rebooting directly from Windows. You can try the following steps to resolve the issue:

1. Perform a cold reboot: Completely power off all components. This is usually achieved by holding down the power button for over 30 seconds to clear lingering ACPI hardware states.
2. Reset KScreen configuration: Clear the display management configuration so a fresh one can be generated. Remove the setup directory using rm -rf ~/.local/share/kscreen/.
3. Regenerate locale files: If error logs indicate a missing language environment variable, regenerate your system locale files.

Sidenote

Adding the kernel parameter 3 in systemd-boot boots directly into the command-line console interface (multi-user mode) without loading the display manager.