I just freshly installed Leap 15.0. After first starting with Gnome I wanted to check out the different Desktop options. I logged out and loaded KDE Plasma, working fine. Then I tried KDE Plasma wayland (or so) which unfortunately directly freezes. The problem the system doesn’t react to anything anymore, nor can’t I switch to non-graphic mode. Thus my only option is a cold restart. The problem now is that I’m the only user and all settings seem to be the way that I directly logs me in and loads this KDE wayland which then again directly freezes. I am thus only looking for a way to interrupt this during startup to be able to choose gnome or KDE Plasma which seemed to work just fine. Any suggestions how to achieve that. Thanks!
That should help you get to a working console screen. From there you can launch ncurses YaST to disable auto-login.
sudo /usr/sbin/yast
Navigate to System > /etc/sysconfig editor > Desktop > Display manager > DISPLAYMANAGER_AUTOLOGIN and remove the user name there. Save the changes and exit. Once, that’s done you should be able to reboot and be presented with a login screen where the desired desktop session can be chosen.