Last night, I run pacman -Syu
update and let it run overnight.
it failed when I woke up, I didn't notice it and restart for newer kernel. Then the WM (sddm) fxxked up. I try to reboot it into mutli-user mode and reinstall kde plasma. it shows bunch of corrupted libraries errors LOL.
I took some time on internet looking for solution, finally found one. Reinstall all dependencies + pacman update cache in ram. https://www.reddit.com/.../recover_system_from_crash.../
pacman -Qqdn > pkglist_deps.txt
pacman --asdeps -S $(< pkglist_deps.txt)
pacman --cachedir /tmp/pacmancache -Syu