You want to be independent.
You want to have your own local repo.
You want to stay as close to Arch Linux as possible.
You want to build up your own distro.
ArcoLinux repo will NOT be used.
Alci repo will NOT be used.
Chaotics repo will NOT be used.
Arch Linux repos and our own local repo is all we need and use.
We show you the steps to take.
You will see that you need to login to xfce on the live environment.
Change the deskop environment in the file /etc/sddm.conf or /etc/sddm.d/kde_settings.conf – use xfce or mate or plasma or …