Required

be sure you have already installed minimal archlinux

Minimal KDE setup

sudo pacman -S plasma-desktop plasma-pa plasma-nm plasma-firewall kscreen bluedevil powerdevil power-profiles-daemon dolphin ark spectacle

Display manager

sudo pacman -S sddm

sudo systemctl enable sddm

reboot

Disable annoying kwallet popup

~/.config/kwalletrc

[Wallet]
Enabled=false