**Hi **
I am using tumbleweed and the standard SDDM login screen with portrait monitors.
I used to rotate the login screen by putting an xrandr command in the /etc/X11/kdm/Xstartup file.
After the last update this no longer works.
I hardly doubt that you ever used this on openSUSE though, because openSUSE’s displaymanagers use /etc/X11/xdm/Xsetup by default.
That includes kdm, but also sddm, so try to put your xrandr command into that file.
For sddm this is configurable in /etc/sddm.conf though, so if it still doesn’t work look at that config file whether it contains a DisplayCommand=xxx option.